Nikolai Spassov was born April, 7 1951 in Sofia, Bulgaria and received master's degree in Vertebrate Zoology from the University of Sofia in 1974. His postgraduate specializations (1979; 1981) are in the Laboratory of Paleontology of the National Museum of Natural History, Paris and the Institutes of Paleontology and of Evolutionary Morphology & Ecology, Moscow. From 1977 to the present day, his scientific career was carried out in the National Museum of Natural History at the Bulgarian Academy of Sciences, Sofia (NMNHS). He was elected professor in 2011 and was the director of NMNHS between 2011 - 2020. N. Spassov’s main interests (more than 250 scientific papers) are in the fields of the paleontology, the taxonomy and the evolution of mammals, the biodiversity conservation. He pays special attention to the questions of the early stages of the human evolution and the earliest human occupation of Europe. He is co-author or author of more than ten species and five genera of new to science ancient mammals. He is a team leader of or participant in more than 40 paleontological and zoological projects and field works or paleontological excavations in Bulgaria and the Balkans, Africa (Mozambique), Gobi desert (Mongolia), and countries of Asia Minor, Caucasus and the Transcaucasia. Nikolai Spassov has been the head of the reorganized department of Paleontology of the NMNHS since its creation in 2006, and all the specialists in this direction in the museum (NMNHS) were or are his Ph. D. students. Through his efforts were created the majority of the NMNHS's mammalian paleontological and archaeozoological collections. He received the Marin Drinov award of the Bulgarian Academy of Sciences for scientific merit in 2021.