Edward G. Howe's correspondence is particularly voluminous, especially outgoing letters to sister Annie Lyon Howe, and his wife Mary Elizabeth Barnard Howe who was left to run the household and accounts while he was away teaching and lecturing. Howe was often in need financially, and much of the correspondence to the Barnard family involves debt and property that Howe occasionally managed for them. Other letters of note are from the members of the Dabney family, with whom he became close while in the Azores, and from the Burnham family, whose son he tutored. His career and personal materials contain several diaries, one of which is a detailed and illustrated volume from his trip to the Azores. Also included are materials from the Forward Movement, which he helped establish, and a scrapbook from a trip to Japan.