If you're old enough and social enough to remember, librarians were the pre-Internet search engine. While most people only interacted with a librarian to check in or out a book, their primary function is information retrieval. You just go up to a librarian, say, "Hey, I'm looking for information about X", and they come back to you with a hand curated list of books, periodicals, and other materials which are most likely to answer your questions.