The Angel Of Darkness by Caleb Carr

Set in late 19th-century New York City, the story follows Dr. Laszlo Kreizler, a pioneering criminal psychologist, and his team as they investigate the kidnapping of a Spanish diplomat's infant daughter. As they delve deeper into the case, they uncover a complex web of deceit, corruption, and dark secrets, revealing the sinister nature of the kidnapper, a woman who defies societal norms and expectations. The narrative explores themes of justice, morality, and the psychological underpinnings of criminal behavior, all while painting a vivid picture of the era's social and political landscape.