In 1961, a librarian in a municipal archive in Strasbourg caught a visitor tearing pages out of a manuscript and stuffing them into his briefcase. The visitor, it turned out, was a widely respected historian who had done ground-breaking scholarship on the history of Jews in France.

It soon became apparent that this was not the first time Zosa Szajkowski had procured documents by questionable means. He’d been doing so for years, before, during and especially after the Holocaust, and the thousands of pages he’d collected had in turn been sold to important archives throughout the United States and Israel. Why did he do it? Were the thefts acts of bravery, pathology, or greed?

These are among the questions asked by Lisa Leff, a history professor at American University, in her new book The Archive Thief: The Man Who Salvaged French Jewish History in the Wake of the Holocaust. She speaks with Vox Tablet’s Sara Ivry about Szajkowski’s heroism in wartime, his post-war descent into property theft, and the profound and lasting impact his deeds had on the study of French Jewish history.