The book describes Edmund's early years in an exceptionally devout Plymouth Brethren home. His mother, who died early and painfully of breast cancer, was a writer of Christian tracts. His father was an influential, though largely self-taught, invertebrate zoologist and student of marine biology who, after his wife's death, took Edmund to live in Devon.

The book focuses on the relationship between a sternly religious father who rejects the new evolutionary theories of his scientific colleague Charles Darwin and the son's gradual coming of age and rejection of his father's fundamentalist religion. It was immediately acclaimed for its courage in flouting the conventions of Victorian autobiography and is still a moving account of self-discovery. (From Penguin Classics)