Kept by Robert Fowler between 1831 and 1854, the volume includes both diary entries (primarily 1841-1846) and accounts. With occasional commentary on local political matters, commerce, weather, and family matters, the diary is largely a record of Fowler's spiritual concerns and his wrestling with doctrinal matters and the relationship of religion and daily life. An ardent temperance man, he commented on religious topics ranging from the Millerite movement to the resurrection, salvation, and the duty of prayer.

Reporting on the sermons he attended on Sundays at various churches, most frequently Warren Lincoln's Christian Chapel, Fowler writes at length about issues of doctrine and faith, including judgment day; the role of love, joy and peace (written while attending a Universalist Convention in Danvers); the resurrection; the duty of prayer; and salvation. Of special interest are several references to the Millerite movement in the years leading up to the predicted Second Coming in 1843. The "doctrine of the millennium," he wrote, was "wholly unfounded. . . and detrimental to the cause of religion, being calculated to allay the fears & lead people to put far away the evil day." In February 1842, he records attending a series of meetings held by the famous Millerite Charles Fitch and the otherwise unidentified Mr. French on "Mr. Millers theory or the end of the world comeing in the year 1843." Fowler wrote: "This both of them Gentlemen stated in bublic [sic] they undoubtingly believed would take place and Mr. Fitch state it was clear to his mind as a sunbeam: and that Christ would make his 2nd appearance in 43, when he would change the dead and living saints and burn up all the wicked together with this terrestrial earth." Interestingly, Fowler refrained from further comment.

The diary also contains some references to Fowler's varied mercantile interests. The earliest records in the volume are accounts from 1831 and 1837, respectively, for hides and lumber (clapboard, hemlock timber, cedar shingles, laths and joists), commodities in which he must have traded extensively. In the text of his diary, Fowler mentions sending fish "packt in ice," apples, flour, lumber, and other goods to ports from New Orleans and South Carolina to Nova Scotia. He refers to a number of individual ships that he appears either to have owned or contracted, including the schooners Freedom, Signal, Van Buren, Florence, and Gem, and the brig Calcutta. One entry from 1846 records having a 65 ton schooner built for him and another from August 1835 makes reference to the sale of the Van Buren. Several references to Newburyport suggest that he may have had ships there.

After September 1843, the diary entries become briefer, more sporadic, and less descriptive, focused primarily on weather, with references to mercantile activities. There are only two or three brief entries at all after 1846.