The story deals with Garp, the son of a technical sergeant disabled by a piece of shrapnel which pierced his head; his mother is a strong-willed nurse who wants a child but not a husband and so uses TS Garp to impregnate herself. Her parents are both wealthy and shocked; Garp's mother raises Garp without their support, taking a position at a boy's school. She becomes a well-known feminist speaker after publishing an auto-biography called A Sexual Suspect (referring to the general assessment of her as an unwed mother). Meanwhile Garp becomes interested in wrestling, sex, and writing: three topics which his mother seems to have a rudimentary and unemotional interest in.
The books contains some elements that appear in almost all John Irving novels: bears, wrestling, Vienna and a complex Dickensian plot that spans the protagonist's whole life.