The corresponding member of the Academy of Medical Sciences of the USSR Professor Leonid Iosifovich Smirnov (1889 - 1955) authored several dozen publications on neuropathology of infections, schizophrenia, cerebral injuries, and brain tumors. Based on his study of pathology of gunshot head injuries during World War II he suggested a doctrine of traumatic on traumatic brain disease. He was the author of the first Russian classification of cerebral tumors and had an impact on the development of neurooncology in the former USSR. The aim of this paper is to show the early development of modern neuropathology at the example of a leading Soviet neuropathologist in the first half of the 20th century and his relevance for modern classification of CNS tumors.