Most of the books found in an academic library and articles found in the library's research databases are scholarly. These sources have often gone through a traditional editorial or peer review process, which means an expert in the field or group of academic colleagues has checked all the facts and arguments the author made and deemed them suitable for publishing. However, you still have to determine whether the book or article is current, objective, and relevant enough for your research.
The library does subscribe to non-scholarly publications such as popular magazines.. Some library databases also include non-scholarly publications like newspapers and trade magazines as well so regardless of where you are searching for information you should always evaluate your sources for their relevancy, currency, objectiveness, authoritativeness, and accuracy.