This book investigates how a political system based on the values of social democracy could look like in the 21st century. It addresses three main questions: Why are freedom, justice, and solidarity the basic values of social democracy? Which are its main objectives? How can social democracy be implemented? The book explores this from a theoretical and practical perspective. It also compares the different political models of five countries. Authored by the FES Academy for Social Democracy in Germany, this is a good read for Thai citizens who are looking for an introduction to social democratic thinking and practice.