A volunteer's first-person narrative recounts enlistment, embarkation, and life in camp during a military campaign in Mexico. Entries trace daily movements, weather and travel hardships, shipboard and tented quarters, and the routines and improvisations soldiers adopt in the field. The author records candid observations about morale, music and camaraderie, tensions between commissioned officers and enlisted men, and the fatigue and privations of campaigning. Descriptions of engagements include accounts of troop positions and maneuvers, accompanied by a contemporary battlefield map intended to clarify the progress of the action.