"A youthful critic in his twenties, Randolph Bourne wrote a bitter essay in the intellectual magazine Seven Arts, lambasting his fellow intellectuals for lining up so readily behind the war effort. "
"One of the hit songs of 1915, “I Didn’t Raise My Boy to Be a Soldier,” by lyricist Alfred Bryan and composer Al Piantadosi, captured widespread American skepticism about joining in the European war. "
Suggested terms to look for include - diary, diaries, letters, papers, documents, documentary or correspondence.
Combine these these terms with the event or person you are researching. (example: civil war diary)
Also search by subject for specific people and events, then scan the titles for those keywords or others such as memoirs, autobiography, report, or personal narratives.
An additional option is to do a search on a topic and use the "Resource Type" limiter on the left side of the results and choose the option "Primary Sources" - please note this is extremely limiting as most primary source materials are not marked in records with this resource type and you will miss seeing a large number of useful items.