There are many primary sources in library books and ebooks. To find these books, certain keywords are very helpful.
Slave narratives, for example, might be a useful keyword search term.
Most other useful terms are subject search terms. Before you type your keywords, use the drop-down menu under keywords, change it to subject.
To find primary sources in books, the best subject search term is: sources. MAKE SURE YOU ARE IN ADVANCED SEARCH.
Example results with search terms used in image above.
Examples of other possible subject search terms: a person's name, the name of the event, or personal narratives, interviews, diaries, pamphlets, correspondence.
Prominent individuals may have written an autobiography or memoirs. Use the drop-down menu again and change it to author.
Examples of E-Books that contain primary sources. All of these E-Books are current available.
American Military History: A Documentary Reader by 
