Robert Michels is a German sociologist best known for his book Political Parties, which contains a description of the "iron law of oligarchy." He was a student of Max Weber who moved from the Socialist Party to become one of the Italian Fasciss.

He moved to Italy where he became a revolutionary syndicalist.

Writings of Michels

• Political Parties. London: Jarrod, 1915.
• Storia critica del socialismo italiano dagli inizi fino 1911. Florence: La Voce, l926.