In addition to books published before 1920 in Adams Library's catalog, book digitization projects have proliferated over the last decade bringing increasing numbers of books onto the web, for example the Internet Archive, described on the Web Resources tab of this LibGuide. The HATHI Trust full text archive represents a particularly authoritative and well-documented effort. HathiTrust is a partnership of major research institutions and libraries working to ensure that the cultural record is preserved and accessible long into the future. There are more than 100 partners in HathiTrust, and membership is open to institutions worldwide. Although volumes under copyright are included in HATHI Trust, books, reports, and other text documents published before 1924 in the United States are in the public domain, free of copyright restrictions, and are fully readable and searchable in HATHI.
Since the HATHI Catalog is created by library partner institutions, consider using our standard SUBJECT search "World War, 1914-1918" and a LIMIT of Year of Publication BETWEEN 1914 - 1919 coupled with keywords in your research area or the names of individuals, organizations, government agencies, events, etc.