Baron's father was Barnett Bernstein, a Polish-Jewish immigrant to Britain who settled in the East End of London in 1908 and later worked as a master furrier.

During the 1930s, with his friend Ted Willis, Baron was a leading activist and organiser of the Labour League of Youth (at that time largely under the influence of the Communist Party of Great Britain).

Baron became increasingly disillusioned with hard left politics as he spoke to International Brigade fighters returning from the Spanish Civil War.

Baron served in the Pioneer Corps of the British Army during World War II, and was among the first Allied troops to be landed in Sicily, Italy and on D-Day.

Throughout his literary oeuvre, we find recurrent interest also in London life, politics, class, relations between men and women, and the relationship between the individual and society.

[3] Later he became well-known for drama serials like Poldark and A Horseman Riding By, and in the 1980s for BBC classic literary adaptions including Ivanhoe, Sense and Sensibility (1981), The Hound of the Baskervilles (1982), Jane Eyre (1983), Goodbye, Mr Chips (1984), Oliver Twist (1985), and Vanity Fair (1987).

[6] Since Baron died in December 1999 many of his novels have been republished, testifying to a strong resurgence of interest in his work among the reading public as well as among critics and academics.

These include Baron's first book, the war novel From the City, From the Plough (Black Spring Press, 2010; Imperial War Museum, 2019); his cult novel about the London underworld of the early 1960s, The Lowlife (Harvill, 2001; Black Spring Press, 2010; translated into Spanish as Jugador, La Bestia Equilátera, 2012), which was cited in Jon Savage's England’s Dreaming as a literary antecedent of punk; King Dido (Five Leaves, 2009, re-issued 2019), a story of the violent rise and fall of an East End London tough in Edwardian England; Rosie Hogarth (Five Leaves, 2010, re-issued 2019); and his second war novel There's No Home, the story of a love affair between a British soldier and Sicilian woman during a lull in the fierce fighting of the Italian campaign (Sort of Books, 2011; Chinese edition published by Hunan Art and Literature Publishing House, 2013).

His wartime letters and unpublished memoirs (Chapters of Accidents) were used by the historian Sean Longden for his book To the Victor the Spoils, a social history of the British Army between D-Day and VE Day.

In November 2023, the London Review of Books published a lengthy article written by Daniel Trilling that discusses Baron's writing and legacy, with a particular focus on The Lowlife.