The dismissal of civil servants on racist or political grounds in April 1933 marked the beginning of a massive, forced exodus of mainly Jewish scholars and scientists from Nazi Germany - a phenomenon unprecedented in the modern history of academic life. The essays in this volume examine whether that ‘exodus of reason’ lead to significant scientific change, and if so, how that change should be characterised. The volume challenges the focus of earlier work on the ‘intellectual migration’ on losses (for German science) and gains (for British and American science). Instead, the authors proceed from the assumption that the sciences are open, dynamic, and historically contingent systems, and explore the multiple, complex interactions of biographical, social, and cultural circumstances with changes - or lack of change - in the émigrés’ scientific thinking and research.