Cyrus Boyd served as an orderly sergeant in the 15th Iowa Infantry until 1863. His diary details the regiment's movements in the Western Theater of the war, covering much of the same ground as Alcander Morse and the 37th Illinois during the summer of 1863. It must be noted that although never published during his lifetime, this version of the diary was edited by Boyd after the war, when material was added "to round out his account." (2)

William Henry Harrison Clayton was private soldier who rose to the rank of sergeant in the 19th Iowa Infantry, a regiment which served alongside the 37th Illinois during the Prairie Grove and Vicksburg campaigns. He was an observant traveler, and these letters provide an interesting and entertaining look at the life of a soldier in the Western Theater. Clayton was captured at the 1863 battle at Sterling's Plantation in Louisiana and spent ten months moving between various Confederate camps in Texas. His letters narrate his experience in detail.

Benjamin F. McIntyre served in the 19th Iowa Infantry, a regiment which accompained the 37th Illinois during campaigns in the Ozarks, along the Mississippi River, and in Texas. Enlisting as a sergeant, McIntyre mustered out of the regiment as a first lieutenant. This diary provides a candid look at the life of a Union soldier in the Trans-Mississippi Theater and his interaction with the Southern landscape. Its contents are largely similar to Alcander Morse's journal, however, Morse's silence on racial matters is not mirrored in McIntyre's writings. He often comments on the "Corps d'Afrique" and their place in the Union war effort.

This book by the late Michael Mullins is the definitive work on the 37th Illinois. While a few of his facts have been corrected by later historians, it remains the only volume on the history of this Western regiment.