In the United States, Libraries usually participate in a program called ILL (Inter-Library Loan). You can request the book be sent to your nearest branch and they’ll find a library that has it in stock. Just look up “[Your library name] interlibrary loan” in your preferred search engine
Also, librarians will usually be happy (if not delighted) to get you a book they don’t have on-hand. You’re not bothering them!
At mine the computer search will tell you if other libraries in the system have it and you can request it right there and if enough requests come up for a book they don’t own they tend to get a copy.
I bring this up like every chance I get, but check out Libby if you don’t want to go to the library. You just link your library card and you have access to tons of books, audio books, and magazines. I also just found out about Hoopla a couple days ago and will be checking that out as soon as I go get my library card renewed tomorrow. Same principle, access to your library’s stuff, but also includes music and movies as well.
Yeah it’s cool but personally I don’t really like ebooks
You should also know that libraries spend most of their budget not on actual physical books, maintenance, or staff but on subscription fees to the digital library platforms they have. I learned this about my university library and I suspect it’s probably the same elsewhere, especially libraries on college campuses.
Interlibrary loan is the coolest thing, because they bring the book to your library so you don’t have to go elsewhere!
You can also have them send you, as well as return them yourself, through the mail.