His first book The Sportsman's Bedside Book, a book that had grown from an article he had written for the Shooting Times, was published in 1937 by Eyre & Spottiswoode. It was the only book 'BB' did not completely illustrate himself; the publishers insisting that artist G. D. Armour's drawings be included as well. His second book and first work of fiction, Wild Lone (1938), was the story of Rufus, a one-eared fox, and was to become a classic of its time. This time it was completely illustrated by himself using for the first time his trademark scraper-board technique, a style of art that had until then only been used for advertisements.

He wrote two more books Manka: The Sky Gypsy and The Countryman’s Bedside Book, before writing his first children’s book Little Grey Men (about "the last gnomes in England"), this was published in 1942 and won the 1942 Carnegie Medal. Down the Bright Stream (1946) continued the adventures of the gnomes from Little Grey Men; The Forest of Boland Light Railway (1955) and The Wizard of Boland (1973) comprise another well-loved series of gnome stories. Little Grey Men was televised on ITV in the United Kingdom in the 1970s (though not under the original title) and the popular Brendon Chase was also adapted for television (again ITV) in the early 1980s.

In 1949 he had a book published called Be Quiet and go A-Angling under the pseudonym of "Michael Traherne", an experiment he did not repeat. In total he wrote more than fifty books, contributed to more than twenty other books by different authors, and also illustrated over forty more. His last book, A Fisherman's Folly was published in 1987.