An anarcho-syndicalist writer and activist of some prominence, whose politics had a major influence in the Spanish Civil War and the jewish émigré community in London, England (see The London Years). His political ideas had emerged from the failings of late 19th century Marxism/Social Democracy under the Germany's SPD, having seen firsthand the erosive influence of electoralism.
I thoroughly enjoyed reading through Pioneers of American Freedom. Rocker aims to accomplish two things through this book. Namely, to give an overview of Liberal and Radical Thought in America (as the subtitle indicates) and thereby demonstrate the illiberality and inaccuracy of claims that tried to paint anarchist thought as an un-American system of thought imported by immigrants.
He accomplishes these two goals cogently. The book almost reads like an anthology, but without the selections from each author. Thus, he covers a fairly comprehensive set of anarchistic and individualist thinkers. Moreover, he demonstrates that these thinkers not only claimed "Native American" bona fides (by which I mean, not being immigrants or recent immigrants) but also that they drew their inspiration not from European philosophy, but rather directly from the likes of Thomas Paine and Thomas Jefferson. I think that one could improve his work here by turning it into an anthology of American anarchist and individualist thought.
I see this book as a great launching point into exploring the anarchist/individualist tradition as present in the USA in the 19th century. Not only does the reader acquire a basic familiarization with the major names and book titles, but Rocker also provides a rich bibliography that even covers the numerous anarchist periodicals that sprouted up around the country in the 19th century.