The monograph is based on the Country Report for the State of World's Forest Genetic Resources - Bulgaria - 2011, that was submitted to the Commission on Genetic Resources for Food and Agriculture in connection with the project for The State of the Worlds Forest Genetic Resources, FAO, Rome (2011-2013). The structure of the monograph is almost the same as the structure of the Country Report. The main aim of the monograph is a comprehensive review of the results of genetic studies of intra-species variability of forest tree species in Bulgaria by means of morphometric, biochemical and molecular genetic markers, as well as the preservation of forest genetic resources by the methods "in situ" and "ex situ," creation of provenance, half-sib progeny and clonal tests. Special attention was devoted to the national legislation in connection with forest genetic resources and the state of regional and international collaboration in preservation and utilization of the forest genetic resources. The monograph is intended for researchers and post-graduate students in the field of forest genetics and breeding, and also for practicing foresters.