Answering questions for us is easy. The further back along our timeline we go, however, the harder it becomes. What did we do before wikipedia? Well, you could go to a library and search for a relevant book on the subject. But what if your question is obscure or not simply phrased? You'll have to look for a little longer, perhaps doing some real research by skimming one book and using its footnotes to find another.
But what if the library isn't organized by the Dewey Decimal System? You will definitely need the help of a librarian and a master index that describes the organizational system of all the books. And what if the books don't contain footnotes? Now you're really getting into hazardous territory. You'll probably have to use the librarian as a living resource, relying on their knowledge of the contents of their library because they've read most of those books.