Have you ever wondered how you come up with a solution to a problem? How about Newton, when an apple fell on his head and he immediately discovered the law of universal gravitation? Or how about Einstein, who through complex inferences came to the discovery of the theory of relativity? That is, do you come to the correct answer with the help of a sudden insight or step by step, thinking through each step? You will find out what you are capable of when, together with Sherlock Holmes, you solve the crimes whose stories are collected in this collection. After all, the best brain training is detective tasks! In addition, they develop qualities that are very useful in life: observation, thinking, imagination, sensitivity, perception, quick wits, resourcefulness, and the ability to understand the interlocutor. If someone immediately fails to help the great detective, do not be discouraged. It has been proven that the human brain is very plastic. It changes in its development throughout life. Therefore, each of us has a chance to improve our thinking abilities through deductive and inductive exercises that will allow you to think clearly and clearly. The bonus of the collection is 5 exciting quizzes that will allow you to remember all the legendary detectives and the authors who invented them.