Donald J. Sobol, who authored the popular kids detective series Encyclopedia Brown, has died at the age of 87.

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Donald J. Sobol wrote a range of books, but was best known for creating the brainy amateur sleuth Encyclopedia Brown. (Penguin Canada)

The writer's son John Sobol revealed on Monday that his father had died in Miami on July 11 of natural causes.

Born in New York, Sobol served in the army during the Second World War and studied writing after his discharge.

He wrote part-time while working in print media and later as a Macy's buyer. He eventually launched into a full-time career as a freelance writer and novelist. His work — largely targeted to children — spanned history, biography, fiction and fact-filled tomes.

Despite this prolific output, Sobol is perhaps best known for creating the series Encyclopedia Brown — though publishing the books was an act of perseverance, according to Sobol's son.

The first Encyclopedia Brown instalment was rejected by more than two dozen publishers before eventually being released in 1963, John Sobol said.

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Sobol's latest Encyclopedia Brown tale, The Case of the Secret U.F.O.'s, was published in Oct. 2011. He has two instalments forthcoming this October. (Penguin Canada)

The hit series — with each book typically broken down into a collection of connected short stories — follows the mystery-solving adventures of brainy amateur detective Leroy "Encyclopedia" Brown and his fellow sleuthing buddy Sally Kimball.

A staple in North American classrooms and school libraries, the series was also translated into 12 languages and sold around the globe. The books were also adapted for television, film and comics.

Encyclopedia Brown also earned Sobol a host of accolades, including from the Mystery Writers of America, which honoured him with a special Edgar Allen Poe Award for his contribution to mystery writing in the U.S.

Sobol also wrote the popular series Two-Minute Mysteries, based on his long-running syndicated column.

He is survived by his wife Rose, also a children's author and an engineer, and three children: Diane, Eric and John. Sobol was predeceased by the couple's son Glenn.

With files from The Associated Press