This subseries contains letters addressed to Mike Gold from a variety of correspondents, including notable figures in his social, political, and artist circles. The correspondence also includes letters exchanged with colleagues related to his work as a journalist and editor at publications such as Daily Worker, Masses and Mainstream, Morgen Freiheit, People's World, and The Worker. Additionally, it features letters from readers and admirers of Gold's work responding to his articles, columns, and books. Many letters include requests from researchers seeking Gold's expertise on subjects such as socialism, worker's theatre, 20th century American literature, and prominent leftist political figures Gold encountered during his life.