It is 1940. For the past decade, Walter Benjamin - the German-Jewish critic and philosopher - has been writing his masterpiece in a library in Paris, the city he loves. Now Nazi tanks have overrun the suburbs, and Benjamin is forced to flee. With a battered briefcase that contains his precious manuscript of a thousand handwritten pages, he sets off for the border.

After an abortive attempt to escape through Marseilles, he is led by chance to Lisa Fittko, a feisty young anti-Nazi who is taking Jews and other refugees over the Pyrenees into Spain, where they may (with luck) make their way to freedom in Portugal or South America.

Jay Parini interweaves the thrilling tale of this escape with vignettes of Benjamin's complex, cosmopolitan past: his privileged childhood in Berlin, his years with the German Youth Movement, his university days. His close friendship with Gershom Scholem, the eminent scholar of Jewish mysticism, is told in Scholem's own voice. Another important strand concerns Benjamin's vexed love affair with Asja Lacis, a beautiful Latvian Marxist whom he met on Capri in 1926.

The cast of characters here includes the playwright Bertolt Brecht and many other well-known artists and intellectuals who were part of Benjamin's intimate circle between the two world wars.