The book is devoted to the biography of the great Russian chemist Dmitry Ivanovich Mendeleev and, along with a biographical sketch, contains an overview of the scientific, pedagogical and social activities of the scientist. The central place among the description of many publications, chemical and physical studies of Mendeleev is the characterization of works related to the discovery of the periodic law of chemical elements, the creation of a hydrate theory of solutions, etc. Works on theoretical and applied aspects of oil chemistry, metrological studies are also covered. Much attention is paid to the role of the famous textbook D.I. Mendeleev "Fundamentals of Chemistry" and his teaching work at St. Petersburg University. The active civic position of D.I. Mendeleev during student unrest, true and deep patriotism. The book is designed for a wide range of readers - chemists, historians of science, teachers.