Charles Sumner, the famed abolitionist who served as U.S. Senator from Massachusetts between 1851 and 1874, collected more than 18,500 letters sent to him; we have another 7,400 sent from him to others. The letters are organized in two parts. Series I contains letters sent to Sumner; they are presented chronologically. Series II contains letters sent by Sumner, also presented chronologically. An index to the letters, showing the names of correspondents and the dates of their letters, may be accessed here.