Volume 4: Red Union, Red Paper, Red Train, 1905-1910 gathers for the first time approximately 180 articles, speeches, letters, and interviews from the prime years of American socialist and labor leader Eugene V. Debs. These include materials relating to some of the great events for which the Indiana orator is best remembered: the founding of the Industrial Workers of the World (the red union), his move from freelance oratory to employment on the staff of the mass circulation Appeal to Reason (the red paper), and his coast-to-coast 1908 campaign for president of the United States aboard the legendary Socialist Red Special (the red train).

These were years of bitter struggle between concentrated capital and the fragmented and exploited labor movement. The period was marked by the illegal arrest and secretive extradition of Western Federation of Miners officials Charles H. Moyer and William D. Haywood in 1906 and the sensational legal proceedings which followed--activity which garnered Debs' full commitment for more than a year.