began his professional career in radiation research in 1989 conducting experimental studies while a PhD student at the Southern Ural Biophysics Institute (SUBI). His thesis addressed cellular lung immunity after inhalation intake of Pu-239. Dr Sokolnikov joined the radiation epidemiology laboratory of SUBI in 1996 as a researcher, studying cancer effects following protracted occupational exposure to external gamma radiation combined with exposure to internally deposited alpha‐emitting Pu-239 among the cohort of Russian nuclear workers at the Mayak complex. The pattern of exposure in this cohort differs from that in atomic-bomb survivors by the type of radiation (external gamma exposure plus internal exposure to alpha particles) and the pattern of dose accumulation (chronic versus acute). Dr. Sokolnikov participated in a large‐scale study funded by Russian Federal Government together with governments or funding agencies from the European Union (EU) and the United States in 1996. In particular he participated in EU research program INCO‐Copernicus and EU research framework programs 6 and 7. Since 1996 he participated in research coordinated by Joint Coordinating Committee for Radiation Effects Research as a researcher and since 2006 as a Principal Investigator. In 2005, Dr. Sokolnikov became the Head of the Radiation Epidemiology Laboratory and in 2016 became the Head of the Epidemiology Division of Southern Urals Biophysics Institute. He was a member of the International Agency for Research on Cancer committee that prepared the recent monograph (Volume 100D) on effects of radiation exposure. In May 2017 he was elected as a member of International Commission on Radiological Protection Committee 1.