The book highlights the scientific work of the largest Russian chemist of the last century, an outstanding representative of the famous Kazan school of organic chemists. His work on the oxidation of unsaturated organic compounds based on the method he created ("Wagner oxidation") became classical and received recognition in Russia and abroad. The scientist managed to decipher the complex structure of many representatives of the Terpen class, to restore, in the words of Academician A.E. Arbuzov, order where complete chaos reigned for a long time...