In the wake of the First World War, Central Europe saw the birth of new republics and hope for democratic renewal. Women and working-class representatives entered parliaments for the first time, and lawmakers found themselves at the centre of a rapidly changing political landscape. This book explores the lives, work, and networks of interwar parliamentarians, focusing on their navigation of political sociability and their evolving roles on the international stage. Challenging the common narrative of the 1920s and 1930s as an era of insurmountable political division, A Continent of Colleagues delves into the behind-the-scenes world of European politics. Drawing on diaries, letters, calendars, and memoirs from politicians across Germany, Czechoslovakia, the Netherlands, Belgium, France, the United Kingdom, and beyond, historian James McSpadden reconstructs the informal networks and personal relationships that shaped parliamentary life. These cross-party and global connections facilitated legislation, diplomacy, and even personal favours. This book depicts how moderate voices were sidelined and cooperation declined as political parties radicalized. Political debate retreated to private spaces, making governance easier but widening the gap between politicians and the public. A Continent of Colleagues demonstrates how this shift contributed to the rise of anti-democratic movements that later plunged the world into war.