This week's varied reading list touches on business, popular music and divinity. The business book looks at Indian billionaires including the Ambanis, the Adanis and the Mallyas, at excess in a land of inequality. Then, there's an excellent study of how Hindi film music has shaped the national imagination and vice versa with a song for every cultural and political moment. And finally, the latest book from a popular mythologist presents the many facets of the dark god, Krishna.