John Burdon Sanderson Haldane was born in 1892 in Oxford. He was the only son of John Scott Haldane, an Oxford physiologist and colleague of John Burdon Sanderson, for whom Haldane was named, and of Louisa Kathleen Trotter Haldane. Haldane's only sister was the novelist Naomi Mitchison. A studious and sometimes intellectually arrogant boy, he went to Eton and then on scholarship to New College, Oxford, where he achieved first-class honors in both mathematics and literae humaniores. He served in the Black Watch regiment in World War I and was wounded. He was later sent to Mesopotamia and again wounded. In 1919 he became a fellow of New College, where he did research in physiology and began his studies in genetics. He went to Cambridge University in 1922 as a reader in biochemistry, married journalist Charlotte Franken Burghes, and continued his investigations in genetics. At University College, London, he was given...