The article analyzs the development of criminology and forensic sciences and the influence of Russian criminological science on the development of Czechoslovak criminology. One of the most important theorists of the Russian forensic school, who worked significantly with Professor Pješčak, was Professor Rafail Samueljovič Belkin, DrSc. (1926-2001), which fundamentally influenced the Czechoslovak criminology of the time. One of the most important personalities of the current stage of development of the Russian criminal school is acad. prof. E.R. Rossinska, DrSc. The paper defines the scientific and methodological basis of forensic expertise. Its subject appears to be the methodological, legal and organizational regularity of the implementation of forensic expertise with the aim of defining the origin, formation and development of classes, types and kinds of forensic expertise.