To search for books at LSU Libraries you can use either Discovery or the Catalog
Discovery searches both the LSU Libraries catalog and multiple databases at one time. This aggregator will display physical books and e-books held by LSU Libraries as well as those not owned by LSU. You can use the limiters in Discovery to refine your search results
The LSU Libraries catalog will show you only items owned by LSU Libraries. If a URL link appears in a record, the book is available electronically. Records for print books will display a call number and the location "stacks." If you need help locating a book, consult a stacks directory or visit one of the Libraries' service desks.
Note that Discovery also searches the Hathi Trust Digital Library, a collection of 11 million digitized books from more than 50 major research libraries. Most of the books are out of copyright and therefore older, so this is a great place to search for primary sources.