Herman Webster Mudgett was born in 1861 in a small New Hampshire hill town, and he was dead before he turned 35. In the years between, operating under a name he had constructed to replace his own, he built a hotel in Chicago designed to kill its guests, committed a number of murders whose exact count remains in dispute, and earned the distinction of being among the first Americans to whom the word “serial killer”—a term that did not yet exist in his lifetime—could reasonably be applied.

He is remembered most often for his actions during the 1893 World’s Columbian Exposition, which brought 26 million visitors to Chicago and provided him with his largest concentration of potential victims. The shadow he cast over that celebration — a gleaming white city of plaster and electric light that rose from the swampy lakefront and lasted six months before being dismantled—has made him a figure of American legend as much as American history. Erik Larson’s 2003 book The Devil in the White City introduced Holmes to a generation of readers, and the interest has not dimmed since.

Perhaps not surprisingly, the legend has not always been a reliable account of history. His crimes were methodical, deliberate, and systematic in their logic, more like cold engineering than a gothic nightmare. The building he erected on 63rd Street in the Englewood neighborhood of Chicago's South Side had gas pipes running into the walls of bedrooms and doors that could only be locked from the outside. It was the physical reflection of a mind that had decided, with the same clear-eyed pragmatism he applied to all problems, that certain people were worth more to him dead than alive. Put simply, he was not driven by rage or impulse, but he was a systematic thinker and killer.