Rumen D. BOJKOV (1931- 2026) was a citizen of Bulgaria and Canada. He obtained his Ph.D. in physics and mathematics from the University of Moscow (USSR, 1964) and a D.Sc. in atmospheric physics from the University of Rostock (Germany, 1971). He taught courses on atmospheric physics at the universities of Sofia (Bulgaria), Albany (NY, USA), Cairo (Egypt) and Thessaloniki (Greece), and held research positions at the Canadian Meteorological Service as well as at the National Center for Atmospheric Research (USA). For many years he worked for WMO in Geneva (Switzerland) as Chief of the Atmospheric Sciences Division and later as Special Advisor to the Secretary-General of WMO on Ozone and Global Environmental Issues. From 1984 to 2000 he served as Secretary of the International Ozone Commission (IO3C) of IAMAS within IUGG and has been one of IO3C’s honorary members since. Dr. Bojkov published more than 120 refereed scientific papers, a university textbook on atmospheric physics, and he initiated, wrote and edited numerous international reports dealing with ozone issues.