In the summer of 2002, a UC Berkeley law student received an oddly cagey phone call. Was he Tom Bennigson? the caller asked.

Yes.

And did he have a grandmother named Carlota Landsberg?

Also yes.

In that case, the caller had located a painting originally belonging to his grandmother that was potentially of some value.

Bennigson knew that in 1938, his grandmother and his mother Edith, then a teenager, had fled Berlin to escape the Nazis. They'd been members of a fairly well-off Jewish family connected to the banking industry. Aided by friends and strangers who sheltered them, the two women began a yearlong journey that took them through Switzerland, France, Spain, and Argentina before they finally settled in New York City. There, Edith got married and gave birth to Tom. Both of Bennigson's parents died when he was young, and he says his grandmother, who passed away in 1994, made little mention of her flight from her home country, or of what she had left behind.

And now this caller was telling him his grandmother had owned a valuable painting, although the title and artist could not be revealed just yet. Bennigson smelled a rat. "I was kind of waiting for them to say, "Send us a check for $10,000 and we'll do everything we can to recover this painting for you,'" he recalls.

But it was no scam: The call was from the Art Loss Register, an international agency that seeks to recover stolen works. Collectors considering a major buy can consult the register to see whether their intended purchase has a clean history. If it doesn't, the agency works to track the original owners (or their heirs) and negotiate a settlement. In this case, a potential buyer had approached the register to double-check the provenance of a 1922 Pablo Picasso oil painting titled Femme en Blanc (Lady in White). Current asking price: $10 million-plus.

The register's investigation turned up a tumultuous history indeed: Bennigson's grandmother, the agency determined, had indeed owned Femme en Blanc, a portrait of a dark-haired woman sedately holding a book. Before leaving Berlin, Carlota Landsberg had entrusted care of the painting to Justin K. Thannhauser, a renowned art dealer who had been one of Picasso's earliest champions. The dealer also was a German Jew. He had moved to Paris thinking it would be safer, but in 1939, with the writing on the wall, Thannhauser departed for the United States, leaving much of his prodigious art collection behind. The following year, during the Nazi occupation of France, his home was looted and the Picasso was among the works taken.

In a 1958 letter to Landsberg, Thannhauser confirmed that the painting had been in his home, and described the ransacking of his house as witnessed by the domestic servants who remained. "During the four-day-long violent German National Socialist plundering, everything was taken out of the four-story house during the night and placed in trucks," he wrote. "I have often tried to find a trace of this oil painting, as well as all the other property that disappeared at the time, but until now without success."

Carlota Landsberg also spent many fruitless years trying to retrieve her painting. In 1969, she even signed a settlement with the German government acknowledging its theft, and was paid 100,000 deutsche marks, or about $27,000. The settlement did not release her claim on the painting -- the money was to be repaid and the portrait returned to her if it were ever found.

Decades went by, and the painting remained lost. Bennigson, the only child of Landsberg's only child, became its sole heir, although he didn't know it existed. Bennigson, a mildly scruffy guy with a distinct unease about discussing large amounts of money, spent most of his adult life studying and teaching philosophy, and then moved to Oakland to enroll at UC Berkeley's Boalt School of Law, intending to become a public-interest lawyer. Then, out of the blue, came the call saying that a valuable Picasso was his to claim.

There was only one problem: It belonged to someone else, someone who lived far away and had no intention of giving it up. So began one of the highest-stakes art lawsuits currently on US dockets.

Last week, after nearly eighteen months of rancorous legal arguments, the state Supreme Court agreed to decide whether California courts can claim jurisdiction in a case stemming from a 64-year-old Nazi crime, involving an objet d'art that has crossed numerous state and national borders. Once that question is resolved, the aggressive courtship of the Lady in White will begin in earnest.

• • • •

Femme en Blanc had been considered "lost" since 1940, but at least one person has known full well where it's been for the past thirty years: wealthy Chicago art collector Marilynn Alsdorf, who had the Picasso hanging in her home. She and her late husband James Alsdorf, who made his fortune as an exporter and glass manufacturer, have been hailed as generous patrons of the arts, particularly after bestowing upon the Chicago Art Institute a four-hundred-piece collection of Asian and Indian works. The Alsdorfs purchased Femme en Blanc in 1975 from New York art dealer Stephen Hahn for what now seems like a very reasonable $375,000. The sales receipt stated only that it had come from a private collection in Paris.

"There was not anything lengthy done to discuss the origins of the painting, and I don't believe that was unusual then," says Richard Chapman, one of Ms. Alsdorf's attorneys. After all, he says, those were the pre-electronic-database days; there was no Art Loss Register to call upon, and researching a painting's origin could be difficult and expensive. The Alsdorfs, he says, were buying through a reputable dealer and had no reason to suspect anything. Ironically, their foundation has helped finance the International Foundation for Art Research, a nonprofit that does outreach work on art authenticity and theft issues, and helped create the Art Loss Register and its database of looted artwork.

The Picasso stayed in the Alsdorf home until 2001, when it was sent to a Los Angeles gallery called David Tunkl Fine Art. It was shown there for one month, then shipped to Switzerland for examination by a potential buyer. The buyer contacted the Art Loss Register for a background check, and lo and behold, Femme en Blanc showed up as a looted artwork from the Second World War.

When he was first approached about the painting, Bennigson says, he understood that the register usually settled disputes without lawsuits. After all, the agency frequently learns of missing artworks because they are in the process of changing hands, and the parties involved are usually willing to negotiate a settlement so the sale can proceed. According to Sarah Jackson, the register's historic claims director, one party will sometimes keep the art and pay a portion of its value to the other; other times, one owner will sell the art and split the proceeds with the other. "Where possible," Jackson says, "litigation should be avoided in favor of mediation."

But Bennigson's case had an unfortunate complication: The Art Loss Register had initially identified someone else as heir. In fact, when the agency first contacted Alsdorf, it claimed the legitimate owner was the Silva Casa Foundation, a Swiss organization that is the legacy of art dealer Thannhauser. Shortly afterward, the register concluded that Bennigson, not the foundation, was the true heir because Thannhauser had essentially been art-sitting.

When first informed of the painting's contested status in April 2002, current owner Alsdorf hired the Los Angeles gallery's attorney to negotiate with the Art Loss Register and the Silva Casa Foundation. Believing the search for a buyer could continue during negotiations, the painting was returned to Tunkl's Los Angeles gallery for the rest of that year. But once the register admitted it had made a mistake, and Bennigson emerged as the new claimant, things got testy.

Initially, Bennigson says, he was willing to negotiate for a portion of the painting's value, but he felt put off by what he interpreted as Alsdorf's cavalier attitude toward his family's loss. "If this woman had been like, 'That's shocking, let's do something about it, let me substantiate this,' and if we'd split it down the middle -- she'd been planning to sell it at that time -- it would have seemed okay to me," he says. "It no longer seems okay to me. I'm sort of embittered." Ultimately, Bennigson demanded the painting be given to him. Alsdorf's legal team refused.

That December, Bennigson hired E. Randol Schoenberg to represent him. It was a strategic choice: Not only was the lawyer based in Los Angeles, where the painting was, but he'd recently made a name for himself in the art-litigation realm by winning a precedent-setting case for his family friend, Maria Altmann. Her uncle had owned six Gustav Klimt paintings that were looted by the Nazis after Austria was annexed in 1938. They'd been stolen as part of the "Aryanization" program that gave non-Jews the right to seize Jewish property. The paintings eventually ended up in the Austrian National Gallery. This summer, the US Supreme Court ruled that Altmann has the right to sue the Austrian government in American courts to recover her family's property. It was a landmark case, something of a surprise victory that may yield a huge payoff for Altmann -- the paintings are worth an estimated $150 million.

With his client's potential Picasso still in Los Angeles, Schoenberg wasted no time. On December 19, 2002, he filed a lawsuit demanding the return of the painting and asking the court for a temporary restraining order to keep it in the state.

But at the crack of dawn on December 20, the Picasso was on a plane bound for Chicago.

Alsdorf's team characterizes the painting's last-minute flight as an innocent coincidence. In her court declaration, Alsdorf claimed she was dismayed at the confusion resulting from the Art Loss Register's mistake. Sensing that any potential sale would be off, she'd decided to have the painting returned to her home. "When I learned that the Art Loss Register had changed its position about the history of the painting, after it had made clear representations regarding its authority to resolve another claimant's claim, I felt very uncomfortable about the reliability of the conclusions that the Art Loss Register had reached," her court declaration states.

Alsdorf's lawyers say their client ordered the painting's return on December 13 -- nearly a week before the suit was filed. It was picked up from the gallery on the 18th and prepared for shipping. At that time, her lawyer says, Alsdorf was unaware she was being sued in California, and the restraining order wasn't actually served on her until three hours after the plane took off.

But Schoenberg and Bennigson view Alsdorf's actions as an attempt to dodge the California courts, which, after all, they had chosen for a reason. The state had just passed a law extending until 2010 the statute of limitations for claims on Nazi-looted artworks. And while the new law was aimed at galleries and museums keeping Nazi-looted art -- not private collectors like Alsdorf -- it was interpreted by Bennigson's team as a favorable sign.

Alsdorf's attorneys, Schoenberg insists, knew Bennigson was the only party then laying claim to the painting. The Silva Casa Foundation had dropped its claim the previous summer, he notes, and the two sides had been in negotiation talks for months. "There wasn't any confusion," the lawyer says. "She just wanted the painting back because she'd be in a better litigation position."

Bennigson believes Alsdorf's team is raising the jurisdictional argument only to delay a trial they can't win. "They're basically just doing everything they can to drag it out. It's like, 'Hey, we have it and you don't,'" he says.

Alsdorf's attorney begs to differ. "This isn't just a methodology of 'How do we escape Tom Bennigson?'" Chapman says. The jurisdictional issue is important, he insists, especially since it's so hard to pin down where any sort of prosecutable crime took place. Was it in New York, where the Alsdorfs accidentally purchased stolen property? Or in France, where the looting took place? It certainly shouldn't be in California, he says, since the painting never changed hands there, nor had Alsdorf lived or conducted business in the state.

So far, a Los Angeles trial court and a state appeals panel have taken Alsdorf's side. But even if the state Supreme Court rules in her favor, the fight will simply relocate to Illinois, and the jurisdictional bickering will have been a mere warm-up act for the main event.

• • • •

In the impending battle over ownership, the art collector's argument goes like this: Alsdorf is the only person in this fight with a bill of sale, and she bought the painting in good faith.

"She didn't do anything wrong and she paid real, live money at the time," attorney Chapman says. Since he's in pre-litigation, he won't say too much about how he'll defend his client's claim, except that he intends to raise a number of very pointed questions: "You say you owned it -- how do you know?" he says. "How much was it? Where is the bill of sale? How do you know it was stolen? Did someone file a police report? Did they arrest anyone?"

The lawyer is well aware he'd be asking the impossible. "Of course you can't answer these questions -- we're dealing with wartime in France," he concedes.

Bennigson dismisses as ludicrous the expectation that his grandma would have taken her receipts with her as she fled Berlin. "If you think of somebody being a refugee across Europe, they're not going to carry a filing cabinet of papers with them," he says. But although the law school grad can't produce a sales receipt, he can produce other documents linking his grandma to the Picasso, including the Thannhauser letter, an inventory of art stolen from France by the Nazis that includes the painting, the settlement papers from the German government, and a 1927 art catalogue that lists the painting as the property of the Landsbergs. "In this case there's really a clear paper trail," he says. On top of that, Schoenberg says, if the defense is going to reject Bennigson's family claim to the Picasso, it has yet to produce an alternative history for the painting. "All they have is doubts," he says. "They don't have any evidence on their side."

Schoenberg says that while the law might favor Alsdorf if she had bought a mass-produced item that was later discovered to be stolen property -- say a car -- things are different when you're talking about a $10 million one-of-a-kind Picasso. When buying unique works of art, he says, the prevailing US law is: caveat emptor. "The law is pretty clear that for recognizable cultural property like this, you cannot get good title if the painting has been stolen or looted," he says. In other words, even if the purchaser buys it in good faith, stolen property can never be legitimately sold, and must be surrendered to its original owner.

A unique twist to this case is that each attorney sees the other's side and agrees that no matter which way the courts rule, it doesn't really undo the initial injustice. After all, the truly culpable person in this story -- the person who stole the Picasso in the first place -- remains an anonymous historical figure who likely will never be punished. Schoenberg says this may be one of those cases where everyone involved loses. "There are two victims," he says. "The person who owned it, and the person who bought it in good faith."

It comes as a bit of a surprise to Bennigson's attorney, whose résumé describes a history of primarily business and entertainment law, that he has ended up litigating two of the four most recent high-profile Nazi art theft cases in the United States. In addition to the Picasso and Klimt cases, there was a 1998 standoff over Egon Schiele's Portrait of Wally, seized while the painting was on loan to New York's Museum of Modern Art from an Austrian museum; a Manhattan district attorney claimed it had been stolen from a Jewish family during World War II and should be forfeited by the Austrian government. And this year, actress Elizabeth Taylor has found herself defending against the claim that a van Gogh in her possession, View of the Asylum of Saint-Remy, had been looted by the Nazis.

More surprising, Schoenberg says, is how rare such cases are. The sad truth, he says, is that there are potentially thousands of other Nazi-looted artworks out there, but because most of them are not worth millions, no one will expend the time and money to search for them or litigate for their return. Even the Art Loss Register can't put a number on how many artworks are still missing, although Jackson says the total value runs into the billions.

Wartime art looting is by no means unique to World War II -- consider the thoroughness with which Iraq's museums were raided following the American assault on Baghdad. But the Nazis' organized program of looting was frighteningly efficient, headed by the Einsatzstab Reichsleiter Rosenberg, or ERR, an agency that collected works for Hitler's personal museum as well as others throughout the Reich. But it's hard to pinpoint exactly who would have taken Femme en Blanc off the wall of Thannhauser's Paris home. There were plenty of possible thieves outside the official looting program: rank-and-file German soldiers, Vichy collaborators, or neighbors who ratted each other out to ransack one another's property. "Individual art works were stolen by soldiers from all sides," Jackson says. "Some would have been sold quite quickly, and some would have been taken home as war booty."

The reason Femme en Blanc ended up in the hands of private art dealers, rather than in a German museum, may have to do with the conservative artistic tastes of the Reich. Much of the work of modern masters was dismissed as "degenerate art," not in keeping with the Nazis' cultural ideals. "They probably wouldn't go for a Picasso," muses Dr. Enrique Mallen, a Texas A&M University art history professor who founded the On-Line Picasso Project (TAMU.edu/mocl/picasso). "It would be too revolutionary to them. What we now consider to be fairly realistic, for them it would be too wild."

But even if the Reich's museums didn't want modern artworks, the Nazis knew they were valuable. Instead, Jackson says, "Any works of art stolen that were not destined for a Nazi collection on the grounds that they were modern or avant-garde were usually sold in the thriving wartime art markets, principally in Paris or Amsterdam, or were used for the purposes of exchange -- for example, five Impressionist pictures swapped for two old master paintings."

With time, these looted artworks are slowly filtering back to the legitimate market. But as with Femme en Blanc, their whereabouts in the interim remain an art-world mystery.

• • • •

Here's what we do know about Femme en Blanc: The portrait was painted in 1922 during what's known as Pablo Picasso's "neoclassical" period, a time when he turned from the fractured, Cubist style he had developed with Georges Braque to creating somewhat more realistic portrayals. During the early '20s, Picasso produced multiple canvases and studies of dark-haired women -- usually his first wife, Russian ballerina Olga Koklova, or model Sara Murphy -- quietly sitting, reading, or napping. One of the theories explaining Picasso's return to a more conservative painting style is that it reflected a brief period of tranquility in the artist's home life. It corresponded with his marriage to Olga, the birth of their son Paulo, and a move to an upscale Paris neighborhood where he was surrounded by wealthy patrons for his work. Olga, Mallen says, continually pressured her husband to become a more traditional painter who made portraits of rich people.

Another theory is that it reflected the French national atmosphere of a return to normalcy at the end of World War I. But in Mallen's view, Picasso's about-face can also be seen as a personal revolt against the co-opting of Cubism. "The theory I like best is that he basically wanted to distance himself from what some people were doing with Cubism," the professor says. "They had found a formula and applied it again and again. ... Picasso never liked to paint by the rules. He just didn't like for people to follow a code and stick to it. He's been quoted as saying, 'Never imitate yourself.'"

By returning to more traditional forms, Mallen adds, "he's saying, 'I am Picasso -- I am not among the Cubists. I am doing my own thing and will come back to it when I feel like it.'"

Close attention to Femme en Blanc reveals that Picasso was still toying with ideas about vision and perception -- Mallen, who has seen photos of the painting, cites the woman's unrealistically elongated body and outsize hands. "He probably took that idea of stretching the woman vertically from classical painters like El Greco -- it's normally an indication of spirituality, getting away from daily life. This is one of the few paintings where we see Picasso idealizing Olga, because that marriage is going to go downhill very, very quickly."

Indeed, in the tempestuous years that followed, Picasso would soon leave this style of painting behind. His fame grew, and his love life became infamous. Although he was Spanish by birth and spent much of his adult life in France, his work was firmly embraced in Germany. He found such a receptive audience in German art buyers that, in a strange way, the fate of many of his works became bound up in the fate of the country.

As much as Picasso's more avant-garde works would have repelled the Nazi leadership, his early work was very popular among ordinary German art collectors. "I think it was because he was so structured in his compositions," Mallen muses. "Picasso was interested in line work, and I think that goes with the rational character of the German culture." The first monograph on Picasso's work was written in German, some of his very first buyers were wealthy Germans, and he established lifelong relationships with German art dealers Daniel-Henry Kahnweiler and Paul Rosenberg.

Another German art dealer pops up again and again in Picasso's history -- Justin K. Thannhauser, to whom Bennigson's grandmother would later send Femme en Blanc for safekeeping. He is perhaps best known today as the man who gave the Guggenheim his massive personal collection of works by Cézanne, Degas, Gauguin, Renoir, and van Gogh, but in the early 20th century his main claim to fame was the gallery his family owned in Munich.

Thannhauser was one of Picasso's earliest supporters. Picasso had exhibited in Thannhauser's gallery as early as 1910, and a relationship between them must have been solidly established in 1914, when Thannhauser created a frisson in the art world by paying 11,000 francs for Picasso's Family of Saltimbanques -- making it, at the time, the most expensive painting ever sold. "A lot of people were saying they couldn't believe he had paid so much for that painting and he was quoted as saying, 'I would have paid twice as much,'" Mallen says.

During the first World War, Picasso's popularity amongst German buyers even made him suspect to the French citizenry. He was accused of being "pro-German," and the Germans who bought his paintings were suspected of trying to drive up the price of his work by paying extraordinary sums, the professor points out.

Bennigson says his grandparents weren't extensive art collectors, but they were relatively well-to-do and considered themselves cultured. He doesn't doubt that they would have owned a few works by contemporary artists. According to Schoenberg, Femme en Blanc was initially sold by Picasso's dealer Kahnweiler to an art gallery that in turn sold it to the Landsbergs in 1926 or 1927. Carlota Landsberg owned it for about a dozen years before sending it to Thannhauser. Then it went missing.

After that things get murky. Nobody can say where the painting was for the next thirty years, whether it was secretly hidden in a soldier's basement, covertly displayed by someone who had bought it on the black market, or hung proudly on the wall of an unwitting buyer who didn't realize he possessed stolen art.

According to Mallen, the Picasso On-Line Project archives show that the painting finally surfaced at French gallery Renou et Poyet, which sold it to Stephen Hahn, the dealer who sold it to the Alsdorfs in 1975. Hahn did not return calls for this article.

Should art dealers and buyers in the 1970s, like Hahn and the Alsdorfs, have more closely scrutinized their purchases' histories? Jackson of the Art Loss Register says background checks weren't routine until the last decade. Before that, they were used only to confirm authenticity or when an object was of particular historical interest. Still, Mallen suggests that by then, art dealers should have known to be cautious about works of uncertain provenance coming out of Germany or Austria. In particular, he says, Renou et Poyet was known to deal largely with work from Germany, and even directly from the collection of Paul Rosenberg, one of Picasso's dealers.

"There's all kinds of flags being raised there," Mallen says. A collector might not have known what to ask for, but, he says, "A dealer should have known. If I had found that out I wouldn't have bought that painting."

He pauses. "Maybe it was just: 'Don't ask too many questions you don't want answers to. '"

• • • •

The fight over Femme en Blanc has grown more pressing as the sales value of Picasso's work continues to climb. This year, a Picasso portrait again shattered revenue records when Garçon à la Pipe (Boy with a Pipe) sold for $104 million.

On the jurisdiction issue, Schoenberg expects the California Supreme Court to be more open to his arguments than the lower courts were, especially given his recent victory in the Klimt case. "It's odd that the US Supreme Court has said we can sue a foreign country for paintings that are in that foreign country, but for some reason the California Court of Appeal said we can't sue a woman in Chicago to recover a painting that was in California at the time we filed the suit," he says.

The two years spent getting the case this far haven't done much to soothe anyone's feelings. Bennigson, who graduated from Boalt this spring, says he now hopes to recover not only the painting but also punitive damages for what he considers Alsdorf's attempt to evade California's jurisdiction. This has become much more of a personal fight for him. "Clearly whatever happens in this case is not going to change anything that happened to my grandmother, or other parts of my family where much worse things happened," he says. "Alsdorf is not the perpetrator of Nazi crimes. On the other hand, she is somebody who is benefiting from them, which you would think that a person of conscience would have some unease with."

Chapman cautions that the case should be viewed separately from the shame and horror evoked by the Holocaust, for which his client obviously cannot be held accountable. "If anyone tries to take the emotion of the Holocaust as a way to resolve [the suit]," he says, "it trivializes the event and just makes it a talking point to support a business transaction." It is, after all, a lawsuit about a luxury item. "We're fighting about property," the lawyer continues. "It's not about life and death or about if someone's going to be going to jail or not."

Schoenberg, however, feels that some retroactive justice is on the line. "Stealing paintings was relatively low on the totem pole in terms of Nazi atrocities," he concedes, "but when it comes to what we can do about it sixty years later, returning those paintings is about the only thing left where we can right some of those lingering wrongs."

A victory for Bennigson could set a strong precedent for allowing the families of Holocaust victims to sue to recover their heirlooms, even when that art reappears on the other side of the globe after having changed hands countless times, and when the current owners have no idea they possess stolen property. Who, after all, can say how many other cultural treasures disappeared along with Femme en Blanc? To whom did they once belong, who took them, and where have they been hiding?

If anyone knows, it's the Lady in White. But she remains as quiet as oil on canvas.