The story of the relationship of Franklin Delano Roosevelt with Tammany Hall of New York has never been completely told. FDR’s dealings with the New York machine have received piecemeal treatment in numerous monographs and histories that record his life. In addition, there is a scholarly bias against connecting prominent leaders in society to the mundane political clubs and organizations that keep the wheels of the party turning and get out the vote. Rather, the study of politics is dominated by a perspective that emphasizes the macrocosmic aspects of the phenomenon. Good government advocates, such as Roosevelt, are supposed to be above contact with local machines which are known to be corrupt. In truth, Roosevelt had a very intricate and profound connection to Tammany Hall that lasted over thirty years, whether he was in or out of office. The author tells the complete story of how FDR and Tammany Hall worked out a modus vivendi.