Fifth Business is often regarded as Robertson Davies' most well-known novel. It is the first part of the Deptford Trilogy and is a story of the life of the narrator, Dunstan Ramsay, who functions as a "Fifth Business."

Davies employs many different techniques in the writing of Fifth Business. He discusses many themes in the novel, perhaps the most important being the difference between materialism and spirituality. By spirituality, Davies discusses how religion is not necessarily integral to the idea - demonstrated by the corrupt Reverend Leadbeater who reduces the Bible to mere economic terms.

Davies, being an avid follower of Carl Jung's ideas also employs them in Fifth Business. Characters are clear examples of Jungian archetypes and events are demonstrative of Jung's idea of synchronicity.