Brief Description: The bulk of the collection consists of the fragmentary correspondence of Kopelson with his future wife, Sonia (Sofia) Trachtenberg (Trakhtenberg), who was also a member of the Bund, and with other persons, including a prominent Marxist publicist Ekaterina Kuskova. Letters refer to the organizational structures of the Bund abroad, cooperation with other Russian political groups, financial and technical assistance to the Bund in Russia, and scheduling of meetings, as well as the personal lives of Kopelson and Trachtenberg, such as their wedding and the birth of their son.

Held at: