This collection consists primarily of correspondence (103 letters) between Gamaliel Bailey and his close friends and associates, statesman Salmon P. Chase and U.S. Supreme Court Justice John McLean. Other friends and business associates, including John McLean's wife, Sarah B. McLean, are represented to a lesser extent. Among other things, the letters document the business of the newspapers Bailey edited as well as the business of antislavery journalism more broadly; the abolitionist movement, particularly within the state of Ohio; the political maneuvering of the Liberty, Free Soil, and subsequently, the Republican Parties at the state and national levels; and the political careers and presidential aspirations of both Chase and McLean. The antislavery philosophies of Bailey, Chase, and McLean and how their philosophies were adapted into practical strategy are discussed in considerable detail.

In documenting the establishment of the Republican Party, the letters chronicle: Bailey and Chase's dissatisfaction with the Liberty Party; the Kansas-Nebraska struggle; conflict with the Know-Nothings and the American Party; the Fremont campaign; the struggle between 1856-1859 to preserve the antislavery principles of the Philadelphia platform; and the groundwork for Lincoln's election in 1860.

A few letters and papers of Gamaliel Bailey's wife, Margaret L. Bailey, which relate to her husband, are also included.