Formation and development of the institute of unjust enrichment in Russian civil law

The article examines the evolutionary path of the institution of unjust enrichment in the civil law of Russia as a unique legal phenomenon. The author, based on Roman legal traditions, traces the transformation of this institution through the prism of the pre-revolutionary, Soviet and modern periods of development of domestic law. Particular attention is paid to the analysis of the categories of "acquisition of property" and "preservation of property", which constitute the subject core of the conditional obligation. As a result of the study, the patterns of successive formation of the institution of unjust enrichment are revealed and the need to take into account historical experience in order to improve its modern legal regulation is substantiated.