The book "On Life" is a philosophical research on the nature of life. It is characterized by simple and clear language, although it touches on deep philosophical issues. Tolstoy never stopped thinking about the significance of his life and human life in general, and in this book the reader meets Tolstoy, the anxious thinker and philosopher who does not stop revising and modifying his ideas, just as he did not stop reviewing the rehearsals of his works. This dynamic, non-stop mental process is one of the most important features of this mighty mind.