Alexander Danilovich Popovsky - a famous writer, playwright and popularizer of science, author of biographical books about scientists. The book offered to the reader step by step reveals the inner world of the Pavlovsk "creative laboratory," introduces the reader to all the joys and hardships of the experimenter's difficult laboratory life. In it, a huge will to action, characteristic of Pavlov, is painted with juicy colors, and at the same time, against the background of this adamancy, the torture of hesitation and doubt as inevitable companions of intense creative activity is well deduced. The reader will get a fairly complete picture of the nature and significance of those physiological processes that were first revealed by Pavlov.