Rupert Croft-Cooke was born June 30, 1903 in Edenbridge, Kent, and was educated at Tonbridge School and Wellington College. He began teaching when he was seventeen. He went to Paris that year as a private tutor, then spent two years in Buenos Aires, where besides teaching English he founded and edited the journal . In 1925 he returned to London and pursued a career as a free-lance journalist and writer. Soon after, he opened a bookshop in Rochester, Kent, and took up the antiquarian book trade. At the same time he also entered the field of broadcasting, giving a series of radio talks on psychology. In 1930 he went abroad again, spending a year in Germany, writing, and later lecturing in English in Switzerland and Spain. He joined the British Army in 1940 and saw service in Africa and India. After his discharge in 1946 he returned to writing and produced several works reflecting his military experience. He became the book critic for in 1947, a position he held until 1953. He died June 10, 1979.

One of the most prolific writers for the British mass market in the 20th century, Croft-Cooke produced countless magazine and journal articles and more than 125 books--everything from co-books to political commentary, from books about circuses to steamy romances. His greatest success, however, came in the genre of detective fiction; he published nearly thirty detective novels, mysteries and thrillers.

His first book, , a collection of poetry, was published in 1922, when he was nineteen. When, shortly after the appearance of his Songs, another of his works precipitated a suit for slander, his publisher, in order to recoup losses he had suffered, forced Croft-Cooke to produce ten books without renumeration. After a self-imposed two year-long exile in Argentina, he returned to England in 1925. He continued to write and his work appeared in the literary magazines New Writing, Adelphi, Chapbook, The New Coterie and English Review. In the late 1920s several of his pieces were published in the American magazine, Poetry.

With the coming of the Great Depression in the 1930s, however, Croft-Cooke rejected the "cult of poetry and literature" and embraced the "cult of experience." Characterizing himself as a "writer for the middle class," he produced numerous works in diverse genres for the mass market. In addition to more than twenty volumes of autobiographical writing and several romantic novels, he also wrote books on travel, food and wine, circus life and gypsies. He explored the politics of the Hitler era, creating a near best-seller in , as well as , and . Croft-Cooke's greatest popularity with both British and American readers was based on his detective fiction and thrillers. Using the pseudonym Leo Bruce, he wrote two series of detective novels. The first, begun in 1936, was based on the adventures of Sergeant Beef, a bumbling village policeman. His second sleuth was introduced in 1952. This new hero, Carolus Deane, a witty and urbane gentleman, was the antithesis of Sergeant Beef. Both series of novels created Croft-Cooke's greatest literary success.