A good scholarly book on, say, prisons in 19th century France goes well beyond simply supplying facts. Just imagine that book digitized and available for Googling. [Google] isn't saying exactly how such a search would work, but if it's anything like the current system, you might enter, say, "Nantes+Prisons" and get back hundreds of thousands of "hits." Somewhere in those hundreds of thousands would be a reference to a paragraph or more in our book. If you found it, what would you do with it? Supposing it says " ... there were few murderers in the prisons of Nantes in 1874 ... " and gives you the source of the paragraph. That is all but useless. Absent a lot more searching, you have no idea whether there are other references to the subject in the book, and the "information" you have found is almost meaningless out of context.