The collection is comprised of personal papers of Texas author and journalist Dick J. Reavis, specifically those materials relating to Mario Cantú and Güero Medrano, and the Campamento 2 de Octubre. Materials date from 1968 to 2002, and measure 1.5 linear feet plus 1 oversize box. The collection is arranged into two major series: Mario Cantú/Güero Medrano and Campamento 2 de Octubre. A third series, Oversize Materials, also exists for large format items.

The first series, Mario Cantú and Güero Medrano, consists of Reavis' materials that relate to Cantú, Medrano, and the Partido Proletario Unido de America. In the subseries Written Works are copies of articles that Reavis wrote for various magazines such as and , as well as multiple drafts leading up to the published articles. Also included are books with information about the PPUA, Medrano, and Cantú. Two of the books Reavis wrote, and one, written by friend and former guerrillero Ramón Pérez, he translated to English. Correspondence contains letters written by Mario Cantú to Reavis from his European exhile and letters Cantú wrote in the name of the "Comité Europea de Solidaridad con el Pueblo Chicano." There is also various correspondence from Medrano and other leaders of organizations with which Cantú was associated. Reavis took most of the Photographs on his trips to Mexico to meet with Güero Medrano and other PPUA supporters. There are also pictures of Mario Cantú and some unidentified photos. In Business Expense Records there are bills, expense vouchers, and requests to NBC News for reimbursement from Reavis' October 1978 trip to Mexico. Finally, the subseries Research Materials consists of clippings, printed materials, and written works by and about Mario Cantú that Reavis had saved or been given. It also contains clippings and printed materials about the PPUA, Mexico and Immigration, and various other topics. One folder contains copies of relevant clipping from periodicals that were removed to be cataloged. There is also a book by Elena Poniatowska with information on Güero Medrano that includes photos taken by Reavis, as well as a collection of journal notes Reavis took on the subjects he studied during his work in Mexico.

Series two, Campamento 2 de Octubre, contains materials pertaining to the Mexico City squatter camp which Dick J. Reavis visited in 1977. In the first subseries, Written Works, are drafts of an article about the campamento written for the leftist publication . Correspondence contains letters from Pancho de la Cruz, president of Campamento 2 de Octubre, as well as other leaders, written in the name of the settlement. There are also several letters that Reavis wrote to his wife during his stay in the camp. The subseries Photographs consists of general photos taken by Reavis of 2 de Octubre and surrounding Mexico City. Also included are photographs of Pancho de la Cruz and Reynaldo Olivares. In Business Expense Records are various receipts from Reavis' 1997 trip. The last subseries, Research Materials, contains clippings, printed materials, publications, and Reavis' notes. There are also clippings of periodicals, including campamento newspapers, the originals of which have been removed from the collection to be cataloged.

Oversize Materials, the third series, includes large format items housed in one oversize box. There is a poster of Güero Medrano advertising the Partido Proletario de Mexico, as well as various other large printed materials including a restaurant menu, and political posters and publications.