This chapter has three parts. The first part introduces the reader to the concept of international double taxation and explains how it arises. The first part also provides a brief overview of the various theories of taxation which were influential at the time and informed the discussions of the League's Experts. The second part of the chapter discusses the economic and political conditions of the 1920s to place the book in context. The third part of the chapter provides a brief overview of the formation of the League and its structure. It then explains how the League came to be involved in the effort to address international double taxation.