Charles Darwin’s discovery of evolution is common knowledge but Darwin the person is barely known. Even on his 200th birth anniversary this year — he was born in England on Feb. 12, 1809 — much has been said about his works but little about his inner life of contrasts. Darwin loved the natural world from childhood. He roamed the wilderness to study insects while neglecting Greek and Latin, the essential subjects. He said of his schooling, “I was considered by all my masters and by my Father as a very ordinary boy, rather below the common standard in intellect.” Sent...