The 76 nights when Hitler sent the Luftwaffe over London made of Greene a connoisseur of danger. Greene took an almost religious pleasure in the devastation. This was judgment indeed of a world he had always found sordidly inadequate. At last it was under nightly condemnation. The war also made him a spy.
Spies are war's theologians.
While whole societies deal in the simple absolutes of life and death, the moral certainties of friend and foe, the spy inhabits a half-world of obscure ends and means, of casuistic niceties of revelation and interpretation. Greene took to spying with the nearest thing to enthusiasm his depressed nature could allow. A stint working in West Africa for M.I.6 was followed by assignment to the Portuguese desk in London, where he ran agents in Lisbon's notorious wartime hall of mirrors. London scotched that one. Spycraft undoubtedly appealed to that side of Greene's nature that found practical jokes engaging.