Conference interpreting is a relatively young profession. Born at the dawn of the 20th century, it hastened the end of the era when diplomatic relations were dominated by a single language, and it played a critical role in the birth of a new multilingual model of diplomacy that continues to this day. In this seminal work on the genesis of conference interpreting, Jesús Baigorri-Jalón provides the profession with a pedigree based on painstaking research and supported by first-hand accounts as well as copious references to original documentation. The author traces the profession’s roots back to the Paris Peace Conference of 1919, through its development at the League of Nations and the International Labor Organization, its use by the Allied and Axis powers as they decided the fate of nations in the years prior to and during World War II, and finally its debut on the world stage in 1945, at the Nuremberg Trials. Available for the first time in English, this account will be of interest not only to scholars and students of interpreting but also to any reader interested in the linguistic, social, diplomatic, and political history of the 20th century.