This book is the third volume in a trilogy that traces the development of the academic subject of International Relations, or what was often referred to in the interwar years as International Studies. This volume explores how International Relations progressed through the 20th century looking specifically at World War II, from the looming world war to the post-War reconstruction in Europe. This one of a kind project takes on the task of reviewing the development of IR, aptly published in celebration of the discipline's centenary.