Series 1 contains publications on war resistance, conscientious objection, and peace. Comprised of works that question militarization and American Cold War-era politics, the series also includes articles on the philosophy and practice of non-violence. A significant portion of the series consists of the publications of War Resistance, The War Resister, and The War Resisters League from the 1940s through1960s.

The largest series in the collection, Series 2 (Socialism) contains three boxes that can be divided roughly into three portions. The two largest and most personal consist of Siteman's correspondence with the novelist Arthur Mark Harris, on the one hand, and with Frank Zeidler, Socialist Mayor of Milwaukee on the other, dating between 1948 and 1960.

At the time of his correspondence with Siteman, Harris was writing a dissertation on the pacifist Randolph Bourne and was referred to Siteman for help. From 1954-1956 Harris and Siteman corresponded regularly about Bourne, developing a cordial relationship. For his assistance, Siteman was sent copies of Harris's newly published books South Paw and Bang the Drum Slowly (neither present in the collection). Siteman was not shy to critique Harris's work: he did not care too much for South Paw and missed the overall message Harris was trying to convey. Although he wrote that he did not like baseball in general, Siteman did enjoy Bang the Drum Slowly, however in the letter thanking Harris for the book, Siteman politely told Harris not to send him any other books, stating that he knew writers received only a few free copies and that Harris should not waste them on him. Harris also sent Siteman a copy of his dissertation on Bourne, entitled Randolph Bourne: A Study in Immiscibility, which is included in the collection.

The correspondence with Zeidler is of a more personal nature. Zeidler and Siteman were longtime friends and collaborators. From 1985 to 1991, they exchanged letters and ideas on matters of Socialism, world politics, and the state of the Socialist Party. During Zeidler's term in office, Milwaukee grew industrially and never had to borrow money. Despite his success as a mayor, Zeidler failed to see his Socialist ways of administration take hold within the United States. "Socialist ideals of cooperation are combated with every event within the world," he wrote. Although he continued to work for the Democratic Socialist Conference -- material from which is included in the series -- Zeidler seemed to lose faith that Socialism would ever succeed in the United States. Siteman and Zeidler discuss the growing divisions within the party based on agendas like women's right or race, which divided the movement as a whole.

The series also contains several works on Socialist theory and practice, including an array of newspaper articles from 1918 to the 1980s.

Siteman's imprisonment as a conscientious objector and Socialist led him into research on reform of the American prison system. The Prison Reform series includes published articles and works, not only from the United States but from countries ranging from Austria to Yugoslavia. Siteman had the idea that prisons throughout the world did more harm than good, and he worked to change the system altogether. The series includes news articles documenting problems in prisons and laying out a vision for positive reform of the basic structure of the system. Several pamphlets focus on the idea of a Socialist reformation of the prison system, arguing that prison should be a place of reform, not simple containment.