A Vítima

Bellow's second novel features Asa Leventhal, sub-editor of a trade magazine, and he is a natural victim; a man uncertain of himself, never free from the nagging suspicion that the other guy might be right. So when he meets a down-at-hell stranger in the park one day and finds himself being accused of ruining the man's life...well, he half-believes it. And because he half-believes it, he can't shake the man loose, can't stop himself being trapped in a mire of self-doubt, can't help becoming...a victim.
First published in the USA in 1947, and in the UK a year later. It first appeared in a Penguin edition in Britain in 1966.