Post Office, by Charles Bukowski, is the self-revelation of Henry ("Hank") Chinaski. Henry is a middle-aged alcoholic willing to buck any system, void of ambition, yet exhibiting superior intellect and reasoning. Having awakened from a terrible drunken spree, Henry looks back at a career that has broken him physically, and at the sexual and gambling adventures that have kept him going.

Henry ("Hank") Chinaski is a middle-aged alcoholic with an attitude. With Betty, his "shackjob," he drinks away their income in an open relationship. Henry joins the U.S. Postal Service accidentally, signing on for an allegedly easy job helping to deliver Christmas cards. He goes on to become a sub, and finally takes the exam to become a regular mail carrier. He works under a sadistic supervisor, The Stone, an archetypal villain who shrewdly maintains buddies in high places, allowing him to work the subs to death. The daily grind of delivering mail in rain, and dealing with dogs and crazy people, is grinding both physically and emotionally. Two old-timers fail, one becoming a thief and the other suffering a breakdown. Betty tires of Henry and kicks him out.

Henry marries a beautiful, oversexed, rich and crazy Texas girl. He enjoys small-town life in Texas with his odd in-laws (except being chased by buffaloes), but follows her back to Los Angeles. On the job, Henry draws another nasty supervisor and a seemingly impossible workload. Henry alludes to the many menial jobs he has had. After a bad fight, Joyce serves divorce papers to Henry, who would have preferred a more direct approach. After making love for old time's sake, he moves out and does not contest the divorce. Henry and Betty get back together briefly and tragically. Ironically, Christmas, which she dearly loves, does Betty in as she drinks herself to death on alcohol the couple receives as a gift. Her funeral is a miserable affair. After, Henry goes to the track, having regularly found luck following funerals in the past. There he meets Vi, a postal colleague, and they have an unsuccessful one-night affair in which he is too drunk to perform.

With Vi behind him, Henry enjoys brief but brilliant success at the track, giving him a taste of the high life. He feels important with Mary Lou, whom he rescues from being evicted for intoxication, and they enjoy themselves until Henry discovers he is being set up for a mugging. He implies that she could have gotten far more out of him by staying with him than by letting her boyfriend roll him. His luck gone, Henry returns to work at the post office during the Los Angeles riots. He lives with a hippie writer, Fay, with whom he has a daughter, Marina. When the baby begins crawling, Henry is abandoned, again without being told directly. With his daughter in New Mexico, Henry finds himself in declining health, and his supervisor is out to get him. He receives a series of four official notifications of the Post Office's intention to discipline and dismiss him for absenteeism. Henry details the physical and emotional burden of clerical work, describes encounters with a stubborn, procedurally minded counselor, a fire he accidentally starts, and his decision to resign without complaining about anyone or anything. He goes on an extended drinking spree after which he wakes up and decides to write this novel.