Harry Keating first got to know Kensington Gardens in 1956 when he moved to London to work as a journalist on the Daily Telegraph. In Kensington Gardens Once contains twelve stories featuring different aspects of the Gardens.

He published his first detective novel in 1959, and since then he has written well over thirty novels, mostly crime, as well as numerous short stories and number of critical works on crime fiction, which earned him the American George N. Dove Award in 1995. The Perfect Murder, the first of many books about Inspector Ghote of the Bombay CID, and The Murder of the Maharajah were both awarded the Crime Writers' Association's Gold Dagger.

Gwen Mandley has illustrated the book with twelve drawings of Kensington Gardens. After studying at the Manchester School of Art, Mandley worked as an artist for Oldhams Press before serving in the ATS during the Second World War. She was awarded an MBE for her work in the War Office. After the war, she became Art Director of the Civilian Bureau of Current Affairs, and later headed an art studio for a leading advertising agency. She is a member of the Council of the Chelsea Art Society.

During a writing career spanning forty-five years, H.R.F. Keating has won many honours, most notably the award of the CWA Cartier Diamond Dagger in 1996 for a lifetime's achievement. Since 1985 he has been president of the Detection Club in succession to some of the greats of British crime fiction, G.K. Chesterton, Dorothy L. Sayers, Agatha Christie and Julian Symons.