India, Nov. 8 -- On an evening in 2016, Sumana Ramanan attended a private Hindustani music performance in south Mumbai. The singer, a man in his early- 70s, specialises in khayal, one of the Indian subcontinent's most scintillating music genres. Although a student of khayal, a regular concertgoer and a writer on music, Ramanan had never heard him before. In this musical detective story, she unravels the secret of the life, art and milieu of the singer Arun Kashalkar, one of the most accomplished and charismatic figures in a wider underground scene that has been preserving this music in its most vibrant hues. The author grapples with the maestro's intricate and rhythm- infused style while exploring answers to fundamental questions about the nature of the mainstream and the reasons for the rise of an underground culture. The Secret Master is thus also an excavation of khayal's history, and a meditation on its aesthetics and contemporary practice....