This collection contains letters of Joshua Gilman Hawkes, a sergeant in Company D, 52nd Massachusetts Infantry during the American Civil War. The letters commence with Hawkes writing from Camp Miller (Greenfield, Massachusetts). In a letter to his sister, Hawkes describes camp life, discusses personal acquaintances, and briefly mentions the Emancipation Proclamation. In successive letters, Hawkes reports movements of and conditions aboard the steamer Illinois and describes conditions in the Mississippi Delta and at New Orleans. In addition to relaying descriptions of skirmishes, troop movements, and incidents of camp life, Hawkes describes in detail his 1863 New Year's dinner and frequently describes in detail food and drink served in camp and found through foraging. He also relates the story of a runaway enslaved person and provides several lengthy descriptions of and anecdotes about contrabands and African-American soldiers. Hawkes expresses opinions on the conduct of the war and is critical in his assessment of the high command and the Lincoln administration, as well as the newspapers of the day. Elsewhere, he writes of lice and fleas, the lack of hygiene among New York regiments, and the southern terrain and climate.

Also within the collection are a few antebellum items, including "A Description of a Virginia Christmas," a poem written by Mary Hawkes in 1852; an anonymous Valentine poem; character references written on Hawkes' behalf; and receipts for life insurance premiums. The collection also contains correspondence received by relatives following Hawkes' death. Included is a letter from J. W. Larkin intended for Hawkes and offering him a lieutenant's commission in a United States Colored Troops regiment. Among the remaining letters are several from friends and former schoolmates, containing memorial tributes to Hawkes. An 1870 letter from Hawkes' Amherst classmate Henry W. Smith is accompanied by a biographical sketch of Hawkes.

Many of the letters are marked "copy," and these copies appear to have been made by a family member, probably sister Mary Hawkes, and probably shortly following Hawkes' death. Some of the original letters of condolence in the collection are accompanied by copies in this same hand. A few of the letters are accompanied by typed transcripts.