Caleb Carr was born in Manhattan and grew up on the Lower East Side, where he still lives. He attended Kenyon College and New York University, earning a degree in history. He writes about a group of people in New York who undertake to solve crimes using "profiling". Dr. Laszlo Kreizler is the world's first "profiler," or forensic psychiatrist. He has rescued young Stevie Taggart from the street life and Stevie is the narrator of this book. A black man works for Dr. Kreizler and his name is Cyrus Montrose. Then there is Miss Sara Howard an early feminist and starter of her own private investigations company. Add to them the Jewish brothers, Marcus and Lucius Isaacson who are policemen despite the anti-Semitism in the NY police department and a reporter named John Schuyler Moore. They had, together, solved the Beecham case in "The Alienist" and are back together to solve the kidnapping of an 18 month old baby girl, daughter of a Spanish diplomat who orders his wife NOT to look for their daughter.
The group live in Lower Manhattan in 1897 and come against all the problems that plagued New York at the time: gangs, police corruption, anti-Semitism, racism, sexism, policital relationship between America, Spain and Cuba, Tamany politics, drugs and prostitution, etc.