La responsabilità e la solidarietà nella lotta operaia: rapporto letto alla "Freedom Discussion Group" il 5 dicembre 1899 [Responsibility and Solidarity in the Workers' Struggle: report read to the "Freedom Discussion Group," December 5, 1899]. Barre: Casa ed. L'Azione, 1913.

Max Heinrich Hermann Reinhardt Nettlau (b. 1865 – d. 1944) was a German anarchist and historian. Raised in Vienna, he lived there until the anschluss to Nazi Germany in 1938. Nettlau retained his Prussian (later German) nationality throughout his life. A student of the Welsh language, he spent time in London where he joined the Socialist League and met William Morris, and anarchists such as Errico Malatesta and Peter Kropotkin, with whom he remained in contact for the rest of his life. 

In the 1890s, realizing that a generation of socialist and anarchist militants from the mid-19th century was passing away and their archives of writings and correspondence being destroyed, he concentrated his efforts and a recent modest inheritance from his father on acquiring and rescuing such collections from destruction. (Much of that collection made its way in the 1930s to the International Institute of Social History in Amsterdam.) He also made many interviews of veteran militants for posterity.

Nettlau wrote biographies of many famous anarchists, including Mikhail Bakunin and Élisée Reclus, as well as one of Errico Malatesta, q.v., published by Il Martello in New York in 1922. He also wrote a seven-volume history of anarchism.