Sergey Ivanovich Ognev was a scientist, zoologist and naturalist, remembered for his work on mammalogy. He graduated from Moscow University in 1910, the same year in which he published his first monograph. In 1928, he became a professor at the Moscow State Pedagogical University. He published a variety of textbooks in zoology and ecology. His magnum opus, Mammals of Russia and adjacent territories, was never completed.