The more adult-themed books of the mid-1970s met with a mixed reception and Garfield returned to the model of his earlier books with John Diamond, which won a Whitbread Award in 1980, and The December Rose (1986). Most notable at the time was a series of linked long short stories about apprentices, published separately between 19, and then as a collection, The Apprentices. The Strange Affair of Adelaide Harris (1972) is a black comedy in which two boys decide to test the plausibility of the tale of Romulus and Remus, using the baby sister of one of the boys. The Drummer Boy (1970) was another adventure story, but concerned more with a central moral problem, and apparently aimed at somewhat older readers, a trend continued in The Prisoners of September (1975), republished in 1989 by Lions Tracks under the title Revolution!, The Pleasure Garden (1976) and The Confidence Man (1978). Garfield, Blishen, and Keeping collaborated again on a sequel, The Golden Shadow (1973). It won the annual Carnegie Medal for the best British children's book. In 1970 Garfield's work started to move in new directions with The God Beneath the Sea, a re-telling of numerous Greek myths in one narrative, co-authored with Edward Blishen and illustrated by Charles Keeping. Yet another is Black Jack (1968), in which a young apprentice is forced by accident and his conscience to accompany a murderous criminal. Another is Smith (1967), in which the eponymous hero, a young pickpocket, is accepted into a wealthy household it won the Phoenix Award in 1987. Devil was the first of several historical adventure novels, typically set late in the eighteenth century and featuring a character of humble origins (in this case a boy from a family of traveling actors) pushed into the midst of a threatening intrigue.

His second book, Devil-in-the-Fog (1966), won the first annual Guardian Prize and was serialised for television, as were several of his later works ( below). In that form it was published by Constable in 1964. saw its potential as a children's novel and persuaded Garfield to adapt it for younger readers.

Garfield wrote his first book, the pirate novel Jack Holborn, for adult readers, but an editor at Constable & Co. In 1964 the Garfields adopted a baby girl whom they called Jane after Jane Austen, a favourite writer of both parents. After the war Garfield worked as a biochemical laboratory technician at the Whittington Hospital in Islington, writing in his spare time until the 1960s, when he was successful enough to write full-time.

Mr Corbett's Ghost by Leon Garfield