Peter Mark Roget--polymath, eccentric, synonym aficionado--was a complicated man. He was a scholar obsessed with his work, yet he had an allure that endeared him to his contemporaries--not to mention a host of female admirers. But most notably, he made lists. Roget longed for order in his chaotic world. His father's premature death and the mental illness of his mother and sister threatened to plunge him into his own madness. And so, at the age of...