Born in London 1844, died in Paris 1916; socialist, later syndicalist; main organizer of the Fédération Jurassienne; pedagogical and historical writer, published Progrès, edited La Solidarité 1870-1871 and from 1871 the Bulletin de la Fédération jurassienne; together with Michail Bakunin he was excluded from the International Working Men's Association (IWMA) at the Congress in The Hague in 1872; after 1874 the virtual leader of the 'antiauthoritarian' International; went to Paris in 1878 and withdrew from the movement; editorial secretary for the Revue Pédagogique, contributed from 1877 to the 'Dictionnaire de Pédagogie' edited by Ferdinand Buisson; became a French citizen in 1889; after 1887 principal contributor to the 'Dictionnaire géographique de la France'; became active again in the time of revolutionary syndicalism; supported the Confédération Générale du Travail (CGT); wrote 'L'Internationale. Documents et souvenirs'.

The IISH acquired this collection in 1936 from Lucien Descaves in Paris with financial support of the Centrale Arbeiders-Verzekerings- en Deposito-Bank (the Centrale). The contract was signed 5 July 1936. The collection was mentioned in the Annual Report of 1936 (p. 12-14).

Correspondence with his parents George and Susanne Guillaume, his brothers and sisters and his wife Elise Golay 1862-1864, 1868-1869; manuscripts of 'Causeries sur la révolution française (études révolutionnaires, 3ième série)' c. 1915, 'L'Association Internationale des Travailleurs et les trois procès de l'Internationale parisienne (1864-1870)' published as 'Karl Marx pangermaniste et l'Association Internationale des Travailleurs de 1864 ̉1870' Paris 1915, etc.; notes: 'Extraits de la correspondance de Marx et d'Engels'; file on his publication of 'Excursions et séjours dans les glaciers (extraits du livre Desor)' in the 'Annuaire' du Club Alpin Français; printed material, including copies of La Bataille Socialiste Paris, with articles by Guillaume 1914 and documentation used for articles.

Inventory made by Rena Fuks-Mansfeld in 2010.

Revised for purposes of digitization by Eva van Oene in 2015.

Complete papers digitized as part of the Centrale Project 2012-2016.