Kochi, June 18 Acclaimed Malayalam researcher and author P. Thankappan Nair (91), who spent more than six decades in Kolkatta and is known as the most famous 'Barefoot Historian' of the City of Joy, passed away near here on Tuesday.

With as many as 61 books to his name, Nair did all his typing work on a 1964-make Remington typewriter.

After reaching 'Calcutta' in his early twenties, Nair began his career as a typist. He later wrote extensively on the history of the city, and was honoured with a D.Litt by the Burdwan University.

In 2018, he returned from Kolkatta and settled down in his hometown Paravur near here.

Nair is survived by his wife, son, and a daughter.