Combining the American history and social background, this book explores the four phases of Parsons life of the mind through digging deep into the voluminous archive materials. From the New Deal and the rising of German Fascism to the Second World War, the McCarthy Time and the Civil Rights Movement, Parsons comprehends the development of modern democracy from the sociological perspective and defends it personally. Premeditating the extensive ideological background of these years, the author of the book elaborates Parsons and the political orientation in his research. **