The Encyclopedia Brittanica, 11th edition rivals Wikipedia. This was published at the turn of the 19th century (to the 20th), and it is in the public domain.
Not very good for modern references, but reportedly it was written by authoritative scholars of the day, just like it is now.
It is searchable. I've become so used to searching texts for strings that books have started to annoy me. Yeah, nothing like curling up with a book, though. No, it's not better than sex.