The study of transformation processes in the Central and Eastern European countries, which pass from one to another economic system is a relatively new, multi-layered research problem. Theoretical concepts about their nature and the knowledge and experience for analysis, interpretation and evaluation of transformations have not been sufficiently completed till now. This research is based on the first comprehensive geographical research in Bulgaria "Socio-economic transformation in Bulgaria - peculiarities and territorial differences" (2012). It is updated to 2012 and supplemented with new facts and relevant analysis. Some theoretical issues are concerned. The peculiarities of transformation processes are studied on the example of national economy, agriculture and labour market. The territorial differences are presented at several territorial levels - regional and intra-regional differences in the country and Bulgaria as a part of the Central and East-European countries or of the EU. This book should be especially useful to professionals and students in Geography, Regional, Economic and Social studies, or everyone who is interested in socio-economic changes during last decades.