, I recommend the following books to you, all about the study of human nature and psychology: 1. "Lanxi Detective Collection": The protagonist is a top student in psychology. He helps the police expose the evil human nature behind the case and is good at reasoning. 2. "Hard to Find Proof": The protagonist is a psychologist who returns to the police force to unlock the human nature and psychology behind various cases, involving some horror and conspiracy plots. 3. "Police Lu Ling": The protagonist became a police officer after graduation. He mainly solved cases involving human nature and ethics. He had a background in studying human nature. 4. "Psychochemist": It tells the story of solving a case through psychology and chemistry knowledge. The protagonist has professional knowledge in psychology and chemistry. 5. "Female forensic doctor, come to the bowl": The protagonist was a female forensic doctor who was good at analyzing human nature and psychology. She worked with the male lead, Qu Mo, to solve cases. I hope you like this fairy's recommendation. Muah ~😗