This book was written for parents and teachers by a famous American expert in the psychology of adolescence, based on serious scientific research. It tells in detail about what happens to the body during this difficult period, what are the physiological and psychological characteristics characteristic of age, how not to miss the last chances of education and to use the reserves of brain capabilities, which at this moment are comparable to the “windows of opportunity” of preschoolers, how to remain a friend a growing child and strengthen the foundation of his future happiness and achievements. Published in Russian for the first time.