Gustav Ichheiser presents a tragic example of one of many scientists who were forced to migrate during National Socialism and whose work belongs to the "expulsion of reason" that occurred as a direct result of the spread of National Socialism. His biography is a tragic one both on the personal and the professional level. He was unable to find a permanent occupation in academia after his migration to America, experienced institutionalization due to a diagnosis of schizophrenia, and had a hard time maintaining friendships and personal ties. Various contributions of this volume address either his professional achievements and the misfortune of most of his work having been gone unnoticed or his personal hardship of finding a new life trajectory in exile and how failure in his professional life ultimately led to a failed personal life trajectory. His sociological and psychological theories are analyzed from a historical perspective as well as paralleled to current sociological and psychological theories. It is shown how his developments and formulations can still help in analyzing social and psychological phenomena today. This contribution serves as introduction and gives an overview of the following contributions of this volume.