"A Lesson in Secrets" is an exciting detective book written by popular author Knya Christie. In this book, the main character, private detective Hercule Poirot, receives an unusual task from a girl studying at an elite language boarding school. The case that Poirot has to solve concerns the secrets of the boarding school's past, and captivates the reader from the first pages. In this book, Christie successfully combines intrigue, mysteries and brutal investigations with the complex psychology of the characters. Known for her skill in creating puzzle stories, she proves her talent again in "Secret Lesson". This book keeps the reader in suspense until the last page, making every next step in the investigation unexpected and exciting. "Lesson in Secrets" is an exciting book that will leave a mark in the heart of every connoisseur of the detective genre.