A Nazi composer set a poem born of the trenches of the First World War to music, and a German woman enamored of a Jew provided the voice that would make those verses famous. Broadcast just before 10 o'clock each night by a military radio station, Lili Marlene united and gave hope to the distraught and persecuted of all Europe. The world was cruelly divided into two irreconcilable camps, but Lili Marlene travelled across all the frontiers, moving within an ambiguity that flouted norms and disciplines: it was a product of the Third Reich sung by English and American soldiers, too. How Lili Marlene, the most famous German song of all time, was able to retain its innocence is still a mystery. A mystery this book tries to shed light on.