Series I. Correspondence contains business correspondence and has been divided into four subseries. Subseries A. General Business Correspondence contains correspondence to Nathaniel Mansfield (1796-1863) (who was often addressed as Captain N. B. Mansfield), Nathaniel B. Mansfield (1834-1889), Henry O. Roberts, Justin Rideout, Mansfield and Roberts, and Rideout and Roberts. This subseries also contains correspondence sent, including telegrams. It should be noted that some of the correspondence is illegible due to the fading of the ink. Subseries B. Captains' Letters contains correspondence to and from captains. This subseries also contains letters from captains' wives to Mansfield, Mansfield and Roberts, and Rideout and Roberts, asking either for money or for information about when their husbands are expected back. Subseries C. Other contains correspondence written by other individuals and not addressed to Mansfield or his firm(s). This subseries also contains cable code books which contain the various codes and shorthand used when sending cables, and the keys to understanding them. This subseries also contains a letter book from Long Wharf in Boston, the dates of the book extend beyond Mansfield's death.