How have we learned soldiers' first hand experiences during the Civil War apex?

The US Civil War was the first major war in the world that had mass newspaper reporter coverage. Journalists frequented army garrisons and reported first hand on battles and the experiences of soldiers that they witnessed. Other sources of information on soldier experiences came from letters to relatives, and diaries kept by the soldiers themselves or by family members. Also, several generals in the war such as US Grant and James Longstreet wrote their memoirs on the war which included almost all aspects of their experiences and those of their soldiers.