My brother, John Howlett, who has died aged 78, had a varied career as a novelist, scriptwriter and biographer.

His admiration of the rebel and actor James Dean and his research for the 1975 TV documentary James Dean: The First American Teenager led him to write a biography of the actor the same year and subsequently a West End musical, Dean, which had notable success in Japan – though less so in London.

Screenplays followed for his own Murder of a Moderate Man (1985), then a serial adaptation of Len Deighton’s Game, Set and Match (1988) for Granada TV, as well as several original radio plays for the BBC. He also co-wrote an outline story for a film, Crusaders, which became the basis of Lindsay Anderson’s award-winning 1968 hit, If…

From the mid-1970s John published a series of novels – mainly thrillers focusing on contemporary issues such as nuclear power, air safety, the Troubles in Northern Ireland and the origins of the Aids crisis. His leftwing sympathies and distrust of the establishment characterised these novels as well as much of his other work in the 80s and 90s.

John’s interest in the first world war, sparked by his teenage conversations with veterans of that conflict, allied to the meticulous research that characterised all of his work, provided the basis for Love of an Unknown Soldier (2010), which became the first of a six-volume saga set against the background of the political turmoil of the first half of the 20th century, covering the rise of fascism, the Spanish civil war and the second world war.

John was born in Leeds to Rex Howlett, a senior civil servant, and his wife, Leila (nee Cagna), who was born and raised in Milan. His early writing work was rooted in his experience as a rebellious student at Tonbridge school in Kent and then Jesus College, Oxford, where he studied history. It was with fellow Tonbridgean David Sherwin that he wrote Crusaders, which satirised public school life.

Later in his career, never having been comfortable with the commercial world of publishing, John found new creative stimulus and freedom through self-publishing and re-issuing his work online.

Living in Stone-in-Oxney, Kent, and then in Rye, East Sussex, with his Italian wife, Ada (nee Finocchiaro), whom he married in 1967, he was an active member of his local communities, renowned for his warm hospitality and strong opinions.

He is survived by Ada, their two daughters, Isabel and Suzanne, five grandchildren, and me.