The library does not routinely buy textbooks for courses. Sometimes, a professor will place a copy of a textbook on Course Reserve.
If you are in the library, ask for books on Course Reserve at the Information Desk.
If you need to scan a few pages, there is a photocopy machine by the Information Desk and another on the Lower Level that are set up for free scanning to your email or a flash drive.
If you want to search online, search Primo (the big search box on the library homepage) and limit your search to Course Reserves.