From the Pulitzer Prize–winning coauthor of American Prometheus, inspiration for the box office sensation Oppenheimer, a biography of super-lawyer and political fixer Roy Cohn, whose shocking exploits over four decades have shaped the modern political era, most prominently the ascent of Donald Trump.

From the 1950s to the 1980s, the many dramas of American political life had one common denominator: Roy Cohn. In his twenties, the infamous young prosecutor sent Julius and Ethel Rosenberg to the electric chair, and as the chief aide to Senator Joe McCarthy became the baby-faced symbol of ruthless communist-hunting. By his thirties, Cohn had begun working as the Mafia’s hired legal gun. In his forties, he was an informal adviser to Richard Nixon. In his fifties, he partied with the glitterati at Studio 54 and visited the Reagan White House where he traded gossip with the first lady. Perhaps most significant, Cohn mentored the young Donald Trump, who telephoned the older man daily and studiously emulated not only his mannerisms but core philosophies.

Years after his death in 1986 from AIDS-related complications, Cohn emerged as a central figure in Tony Kushner’s Pulitzer Prize–winning play Angels in America. Cohn’s feistiness, his surly defiance—and, yes, his charm—were frequently flourished to conceal vast insecurities, particularly regarding his closeted sexuality.

A streetfighter, self-promoting hustler, and true Zelig of the dark side, Cohn was a nefarious actor in a startling number of history-shaping events whose influence resonates to the present day.