The collected articles consider the actual problems related to the political changes that have been taking place in the period of 2004-2008 in two key states emerged on Post-Soviet space – Russia and Ukraine. Considerable attention is devoted to the analysis of principal trends, factors and alternatives of post-Soviet societies’ political modernization, role of geocultural and civilizational features in such modernization processes, to the problem of unconformity of political systems shaped in 1990s and their democratic (in form) institutional design to imperatives of real political process. An intensifying divergence of trajectories of political and institutional changes in these two countries has also been traced. The collected articles are addressed to political scientists, sociologists, experts in international relations, students and teachers.