Detectives: Fact or fiction?

Talking About Detective Fiction

Her most famous character is the poet-detective Adam Dalgleish, but some of her novels feature a female sleuth, Cordelia Gray. They tend to be set in dramatic stretches of bleak English countryside, often East Anglia, and are known for their gruesome descriptions of imaginatively murdered corpses.

So who better to read on the topic of detective fiction, primarily (but not exclusively) British detective stories? She records her admiration for Ross Macdonald, Ian Rankin and Sara Paretsky, but the bulk of her account of the detective story is focused on early 20th century English authors.