Use Library Search to find books owned by Temple University Libraries. You can search by author, title, subject, or keyword.
To search for books about World War I, the best way to search is with the phrase World War, 1914-1918
Once you find a book that seems useful, check the list of Subject links in the item's record. Try these links to find additional books on the same topic. For example the subject: World War, 1914-1918 -- Netherlands, will take you to other books on the Dutch in World War I.
Search these databases to find scholarly journal articles on historical topics.