The intellectual roots of anarchism lie in the mid-nineteenth century. The papers of key figures such as Bakunin and Elisée Reclus are preserved at the IISH. The libertarian wing of the First International and its subsequent development is documented in the records of the Fédération Jurassienne and the papers of Jacques Gross and Fritz Brupbacher.
The papers of Gustav Landauer are a rich source for German radical movements.
The papers of Alexander Berkman and Emma Goldman deal with American and Russian anarchists as well as anarchist movements. Latin American anarchism is well represented in the large collections of Ugo Fedeli, Hugo Rolland, and Augustin Hamon.
Anarcho-syndicalism in action is documented in the records of the Confederación Nacional del Trabajo and the Federación Anarquista Ibérica, mostly from the time of the Spanish Civil War. The papers of Rudolf Rocker, Grigori Maximov, Senya and Mollie Fléchine-Steimer, Christiaan Cornelissen, and Augustin Souchy cover almost the entire history of European anarcho-syndicalism. The vast records of the anarchist publishers of Freedom and Fraye Arbeyter Shtime shed light on the practical experiences of the anarchist movement.
The predominance of anarchist tendencies in the student and youth revolts of the late 1960s can be traced in the records of the Internationale Situationniste, Provo (Amsterdam) and the Paris Mai-Juin 1968 collection.
The Italian archives at the IISH bear the hallmark of anarchism. Clear examples of this are the archives of Armando Borghi, which include many documents on Errico Malatesta, the archives of Ugo Fedeli, and Luce Fabbri and her father Luigi Fabbri. The archive of the Partito Anarchico Italiano chronicles the anarchist movement of the 1980s and 1990s.