Zakhary Grigorievich Frenkel is an outstanding Russian hygienist and gerontologist, statistician and demographer, full member of the USSR Academy of Medical Sciences, Honored Scientist of the RSFSR, professor, health care organizer and public figure in Russia. The long, 100-year life of the scientist covered the most difficult periods in the history of our country. He was a participant in the revolutionary movement of the late 19th - early 20th centuries, made a significant contribution to the development of the zemstvo medicine system, was an active participant in the socio-political struggle in the country in the ranks of the Cadet Party (he was a member of its Central Committee), for which he was subjected to arrests and persecution by authorities. Z. G. Frenkel was a participant in the First World War. After the October Revolution, he devoted himself entirely to scientific and teaching activities, but also in 1938–1939. again did not escape repression. During the Great Patriotic War, he did not leave Leningrad for a single day, continuing in the horrific conditions of the siege to engage in the work of his entire difficult life - the fight for the health of the people, for the extension of human life. For specialists in various branches of medicine and everyone interested in the history of science and history Russia XIX–XX centuries