This book argues that considerations of stability and short- and medium-term prosperity are the primary reasons why the EU has promised to enlarge eastward and why the Eastern European nations wish to join. The author believes that the success of a research paper relies greatly on using results from a number of these sources and formulating theories that are as objective as possible to maximize the validity of the findings. Thus, the present document examines the preparation of Bulgaria for future participation in the structural policies of the EU with the purpose of achieving economic and social harmonization on the basis of the introduction of principles of regional and social policy. Structural funds are among the instruments used to achieve the aims of economic and social harmonization, and thus the preparation for their most effective and efficient use during the pre-accession period is very important. Within this context, the book examines the necessary organizational, administrative, legal and financial measures which must be undertaken in the pursuit of successful future participation in the structural funds of the EU.