Hi Leah:
Good question. There are a variety of resources available for books these days. Depending on your timeframe, if a book is not available at a local library, you can certainly request it and they will place an order for one for you to check out later. With the abundance of books available today, I can certainly understand why many libraries or universities do not stock every publication.
The university I attend is online, and has an online student library as well. If books of interest are not available in your public library, the university library is your next best option whether it is on-campus or online. And if it is not stocked, you can put in a request, similar to the process a public library uses.
Thanks for your input.
Patricia