The Deptford Trilogy is the name given to three related novels by Canadian novelist, playwright, critic, journalist, and professor Robertson Davies.

The trilogy consists of Fifth Business (1970), The Manticore (1972), and World of Wonders (1975). The series revolves around a simple act—a young boy hides a stone in a snowball and the throws it at another—and the effect this act has on a number of characters.

The Deptford Trilogy has won praise for its narrative voice and its use of character. Fifth Business, in particular, is considered one of Davies' best novels.

The trilogy takes its name from the fictional small village of Deptford, Ontario, based on Davies' native Thamesville. Davies takes three different viewpoints in each of the novels, and approaches each of the novels in different styles.

Each of the main characters of the series has come by twisting paths from their simple village—and each carries a secret that crosses the lives of the others and drives the plot forward. The greatest secret is one that we are not even aware of until the close of the last book, but knowing it finally answers questions about the relationships of several major characters.

See also Southern Ontario Gothic.

Fifth Business

Fifth Business is narrated by Dunstan Ramsay, a schoolteacher who grows up in the fictional Deptford. The novel takes the form of a letter Ramsay writes to the Headmaster of the school from which he has just retired, wherein he recalls how, as a boy, he ducked the fateful stone-laden snowball intended for him. The snowball hit a pregnant woman who happened to be passing by; she gave birth prematurely as a result. This incident has affected Ramsay's life, and the novel tells how he comes to terms with his feelings of guilt. Intertwined with his story is the life of Percy Boyd Staunton, Ramsay's boyhood friend who threw the snowball, and who later becomes a wealthy and successful businessman.

The Manticore

The Manticore is the story of Percy Boyd Staunton's only son, David. David undergoes Jungian psychoanalysis in Switzerland. During his therapy, he tries to understand his father and his relationship to him. The novel is in fact a detailed record of his therapy and his coming to understand his own life. The novel sheds new light on many of the characters introduced in Fifth Business, including Dunstan Ramsay, who happens to be in Switzerland recuperating from a heart attack.

The Manticore won the Governor-General's Literary Award in the English language fiction category in 1972.

World of Wonders

World of Wonders is the story of Paul Dempster, the son of the woman hit by the snowball, who has grown up to be Magnus Eisengrim, a famous magician. Eisengrim is to portray Robert Houdin in a television movie. During lulls in the filming, he recounts his life, including the incredible obstacles he has had to overcome, and elaborates on his career as an actor travelling through Canada earlier in the 20th century. Dunstan Ramsay is again in attendance, and more insight is gained into the characters of Fifth Business.

Dunstan Ramsay

The narrator of Fifth Business, Dunstan Ramsay, appears as a major character in the other two books in the trilogy, and crops up in several other novels by Davies. He is a gentle schoolmaster with surprising depths and is probably the stand-in for Davies himself. He counsels his students to write in "the plain style", as Davies does—to highlight the story rather than the writer.