Gadgil had a deep and intense relationship with Mumbai, the city of his birth. He loved Mumbai, studied its history, and wrote biographical profiles of many notable historical figures such a Dadabhai Naoroji, Walchand Hirachand and Vishwanath Narayan Mandalik, which have been published as monographs. In "Prarambh", a major and ambitious later historical novel, he approached the history of Mumbai through the figure of Jagannath Shankarshet, a towering public figure from the early 1800s. The biographical novel interweaves his life and works with the social, commercial and cultural evolution of the city in the 19th century, and incorporates as characters Indian and British figures such as Jamshedtjee Jeejeebhoy, Bhau Daji Lad, Governor Mountstuart Elphinstone, who helped shaped Mumbai into a modern metropolis.