Beverly Gage is a professor of history at Yale University. She graduated magna cum laude from Yale University and received her PhD in history from Columbia University. Her research focuses on 20th-century interactions between governments and social movements. Her first book, The Day Wall Street Exploded, examines the September 1920 bombing in front of the J. P. Morgan office. The explosion killed 40 people, and it would stand as the deadliest terrorist attack in US history until the bombing of the Alfred P. Murrah Federal Building in Oklahoma City in April 1995. The book covers many of the themes she later explores with G-Man, which is appropriate since Hoover himself was part of the team charged with investigating the bombing, although they never mounted a successful prosecution. Like G-Man, the book examines how government responds to evolving social conditions, often responding to new threats with harsh tactics and blatant violations of constitutional procedure rather than attempting to understand and address the root causes of violent or subversive behavior.

In interviews regarding G-Man, Gage has said that she generally agrees with the negative public perception of Hoover as a paranoid and authoritarian bully who abused his office, but that focusing on his most obviously negative qualities is not sufficient for a genuine understanding of the man and, even more importantly, how he both influenced and was influenced by American society as a whole.