The Institute for Social Research, which opened in 1924, was something special right from the start. It had its roots in the trenches of the First World War and on the barricades of the revolution. Felix Weil, the communist son of an entrepreneur, had helped to found this new research institute which attracted workers and students, politicians and artists, scientists and intellectuals alike. Another special thing about it was the fact that the Institute was able to continue its work after 1933 in spite of closure, persecution and exile. Key works like the ‘Dialectic of Enlightenment’ were written in California. Philipp Lenhard explores the emergence of critical theory in American exile, and shows how it developed into the Frankfurt School in the early days of the German Federal Republic. Full of surprising insights, this book concisely and vividly illustrates the historical context in which Horkheimer, Adorno, Marcuse, Benjamin and many others became key figures of the 20th century.