Eaton, who teaches at Arizona University, has mastered the facts, but he isn’t an instinctive narrative historian. This is the epic period in which India was invented. The Hindi language, the biryani and to some extent Hinduism (a Persian word) all come from this Persianate age, but Eaton says less on these subjects than on the growth of arable land. Still, his book is a fine tribute to India. Those who conquer it are always, in the end, conquered by it.