During the first two decades of the twentieth century the ideas of revolutionary syndicalism developed into a major influence within the trade union movement. Committed to destroying capitalism through direct industrial action and revolutionary trade union struggle, the movement raised fundamental questions for activists across the world.

Radical Unionism provides an analysis of the dynamics and trajectory of the syndicalist movement in six specific countries: France, Spain, Italy, America, Britain and Ireland, and provides a systematic examination of the relationship between syndicalism and communism.