The monograph offered to the reader is the first domestic study specifically dedicated to the founder of one of the most influential philosophical movements of our time. The first book (Part 1. 1914–1939) was published in 2008 (M., IFRAN). The second part covers the development of the ideas of the Frankfurt School of the “mature” stage (“Dialectics of Enlightenment”, “Instrumental Reason”, etc.). The material used is the lectures and posthumously published seminar minutes of the school, reviews and diary entries of M. Horkheimer, which have not previously been analyzed in the domestic literature. Horkheimer's ideas are presented in the broad context of philosophical, sociological, psychological, literary and political movements of the mid-20th century, as well as in comparison with the theories of his colleagues and friends: T. Adorno, L. Leventhal, etc.