The author has lived in India for thirty years and Indian reviewers have praised his insight into their nation and culture, e.g.
Pankaj Mishra, The National
“Nine Lives remains oddly gripping, and often very moving, in its first-person accounts, framed by minimal explanations, of spiritually-minded people that Dalrymple meets on his travels across the subcontinent. Across the country, Dalrymple comes across instances of popular religiosity and the stubborn persistence of beliefs and ritual practices amid rapid change. Characters rarely allowed into contemporary Anglophone writing about India are given an opportunity to describe their deepest aspirations without the slightest hint of authorial condescension. They speak eloquently of the varieties and specific content of religious experience in India; its remoteness from the political mobilisation of religion, and its role as a marker of identity… The true vitality and continuity of Indian religions is still to be found where most of India’s one-billion-plus population lives. Still widely practised, folk religions and pluralist traditions constitute the norm rather than the exception…
The author's own page about the book http://www.williamdalrymple.uk.com/books/nine-lives-1 calls it "a modern Indian Canterbury Tales which introduces us to characters and takes us deep into worlds we could never have imagined existed," and that is pretty accurate. I thought I knew a bit about India and Indian religion but most of Dalrymple's interviewees are far from mainstream.
Jain nun? Okay.
Tibetan monk? Of course - but this one served in the Indian army after escaping Tibet and re-ordained decades later.
Blind Baul singers?
Tantric practitioners living in graveyards with their collection of skulls?
If it comes your way, grab it. If it doesn't, and you're interested in how religion plays out in people's lives in rural India, look it up and buy or borrow it.