To find books, you can search the three main catalogs:
BGSU Libraries Catalog -- contains books, magazines and journals, videos, music, electronic resources that are owned by BGSU. Almost all of them are located on campus, with some located at the Firelands campus library and the Northwest Ohio Regional Book Depository (those can be requested).
OhioLINK Central Catalog -- contains books, videos, music, electronic resources from academic and some large public libraries in Ohio. Request online, delivery to Jerome Main Circulation desk in 2-3 business days.
WorldCat Catalog -- tens of thousands of academic, public, and special libraries internationally. Got some time, and can't find it in OhioLINK? You can request things not owned by BGSU or OhioLINK via interlibrary loan -- average delivery time is 17 days. It's best to get help from a reference librarian to make sure there's not a faster way to get what you need.