Francis Galton was born near Birmingham, England, in 1822. His impressive talents appeared early. At the age of three, he was already reading, and at four, he was studying Latin. His I.Q. at adulthood was estimated at 200. But as a young man of 22, a fresh graduate of Cambridge, Galton did not continue his training as a physician. His wealthy father had died and left Galton a large inheritance, so the young Galton was free to do whatever he fancied.

For a time he chose to travel, exploring virtually unknown parts of Sudan, Syria, and southwest Africa. Upon his return, Galton published two books about his travels. He was even recognized by the Geographical Society and the Royal Society with various medals and honors. He was also knighted in 1909.

Galton never held any academic or professional post. Instead, he did his experimenting at home or during his travels. His...