The book of Professor I.M. Feigenberg in a popular form acquaints the reader with various aspects of human mental activity. Particular attention is paid to probabilistic forecasting - the mental ability of the brain, the study of which is the main topic of the author's research work. The book highlights some issues of psychophysiology of perception, emotions, memory, certain problems of engineering psychology and pathopsychology. The book is designed for a wide range of readers.