The book offered to readers is a political biography of Jose Diaz (1895-1942), Secretary General of the Communist Party of Spain, a prominent figure in the international labor and communist movement. Jose Diaz lived a short but bright life, having gone through a difficult path from a working anarchist revolutionary to the leader of the Communist Party, the country's largest political party. The period of strengthening and development of the KPI, turning it into a mass party, into a genuine vanguard of the working class is inextricably linked with his name.