This article assesses the contributions of Wilfred Bion and John Rickman to military psychiatry in World War II in the light of their lives and careers before the war. While Bion entered World War II with a distinguished record as a tank commander in World War I and an analysis with Rickman that was incomplete, the Quaker and ex-conscientious objector Rickman was surprised to find himself made a Major in the British Army. The creative partnership which Bion's letters to Rickman document, and which resulted in substantial developments in the understanding of groups, stemmed in part from the ways in which each was able to draw on their earlier experiences and reputations, one as a founding figure in the British psychoanalytic community, the other as a decorated veteran.