The book holdings of the Penn Libraries, whether print or online, are listed in the Franklin Catalog. When searching, you can limit your results using the Online and Book limiters in the left side of the screen.
Franklin Catalog also includes links to works in HathiTrust, a large, academic archive of materials, many of which are in the public domain. If you prefer to exclude HathiTrust results, select Penn under Record Source.
Explore our Penn E-Books Guide.