Lionel Davidson's debut thriller was a massive success on first publication in 1960. The New Yorker said it was 'so enriched with style, wit, and a sense of serious comedy that it all but transcends its kind.' Newsweek thought it 'downright superb', and it won the Gold Dagger Award of the Crime Writers' Association.

Young Nicholas Whistler, dissolute and disillusioned, lives a life of monotony in London. Caught up in a petty money-lenders' dispute, he is sent to Prague to discharge the debt by carrying out a simple assignment. Instead he is dragged deep into the dangerous world of Cold War espionage and the battle for atomic supremacy. Trapped between the secret police and the amorous clutches of the mysterious Vlasta, Nicholas realises he is now a spy, whether he likes it or not.