I had gleefully agreed to review this book, but when I got the copy I scowled. My aging elbows protested that after six medical college years of coping with Gray’s Anatomy and its muscular cousins, they were in no mood for weight-lifting. But it was so well worth the effort. Sure of my knowledge of some sections of medical history, I thought of skipping chunks of the book to read later. Better sense prevailed—and it was as if the dull pages of botany and zoology had been rewritten by magic fingers. Writerly sophistication comes naturally to this doctor-writer, winner of the Pulitzer for The Emperor of All Maladies. The history of the gene is skilfully interlaced with evolution, heredity and eugenics, its future possibilities are made clear, with never a paragraph that could divert or dull the engrossed mind.