The failed attempt to assassinate Hitler in July 1944 by a group formed mainly of aristocratic army officers remains one of the Second World War’s most controversial episodes. The view of the conspirators as doomed heroes sacrificed to the rage of a vindictive tyrant was challenged at the outset by those who claimed that they deserved execution for breaking their oath of loyalty to the Führer. Their motives and integrity have also been questioned. Did they launch their enterprise purely in the name of wounded military prestige, for the sake of salvaging Germany’s national honour? And, as one recent revisionist historian has suggested, hadn’t many of them already fouled their hands with round-ups and massacres among the occupied peoples of eastern Europe?