Vikram Seth had a problem. The Calcutta-born, London-based author had exploded onto the literary scene in 1986 with The Golden Gate, a novel in verse set in California. His 1993 Indian saga A Suitable Boy at nearly 1,400 pages the longest work of fiction in English since the 18th century sold a million copies in Britain alone. Then came some poems, an opera libretto and nothing.
"You don't know exactly what to write about next," Seth's mother, visiting from India, told him in 1994. "Why don't you write about him?" She was referring to another...