This series contains additional correspondence and papers related to Solon De Leon's involvement in labor organizing and education. Correspondence ranges from personal letters from friends spanning several decades to more formal correspondence with organizations with which De Leon was affiliated, including the Rand School of Social Science, League for Industrial Democracy, and the Socialist Labor Party. These records also contains a number of teaching materials related to classes De Leon taught to union workers. These materials also contain some of De Leon's personal writing including plays, sketches, and short stories. It also contains a number of biographical materials related to his father Daniel De Leon.
