We Shall Be All: A History of the Industrial Workers of the World - Melvyn Dubofsky

A nice history of the early IWW. Just to comment on this passage by Dubofsky:

Dubofsky wrote: Industrial unionism, Haywood once said, was [political] socialism with its working clothes on. But after 1913, when Haywood was recalled from the Socialist party's national executive committee, IWW industrial unionists and American Socialists had little in common. American Socialists, optimistic about their future prospects and eager to widen the popular base of their party, subordinated revolutionary fervor to the cause of immediate reform and popular acceptance. Wobblies, more pessimistic about the future and more respectful of capitalism's staying power, tried to instill revolutionary fervor in their adherents. The Socialist Party, unlike the IWW, had no room for men who counseled defiance of the law, neglect of the ballot box, and "real" revolution. (96)

It's worth pointing out that the Socialist Party had a left-wing faction that was less reform-minded than the likes of Victor Berger, Morris Hillquit and other "slowcialists" who emphasized gradual change over direct action and revolution. The magazine International Socialist Review represented this left-wing faction and frequently published articles by Haywood (who was an "associate editor" himself) and supported the IWW. They also defended Haywood against the (successful) attempt to expel him from the National Executive Committee of the Socialist Party in 1913. See the International Socialist Review (Vol. 13 No. 8, February 1913) here for example:

Socialist Party members wrote: Therefore Be It Resolved, That we, the undersigned members of the Socialist Party, believe the action of the New York State Socialist Party in attempting to recall comrade Haywood from the National Executive Committee and to expel him from the Socialist Party to be unwise and unwarranted, and to tend to create dissent and ill-will within the ranks of the Socialist Party. That furthermore, we believe no such action should be taken against any member unless he definitely repudiates political action or some other principle of the Socialist Party.

Be It Further Resolved, That we know Comrade Haywood to believe in political action, and to have been of great service to our party in helping it to solve the difficult problems that confront the working class upon the industrial field. We also believe that instead of exaggerating inevitable differences of opinion, instead of reviving DeLeonistic tactics of personal incrimination, heresy-hunting and disruption, we should make use of the special talents of every member within our ranks, and in this way secure loyal service and co-operation. We believe in a united working class. (623)