There is no library in the game. Well, there is sort of one in the merchant's guild, but those bookcases don't have any greater chance of containing a (random) book than any other. However, the contents of the books in DD are in the file '..\Divine Divinity\Run\main\startup.v2\static\books.000
'. It is not a straight text file, but you can open it in Wordpad (etc) and read/copy the text portions.
Myrthos has compiled some background and FAQs for D2:ED at the Locus Inn
, though most of that deals with the events during and after DD. The D2:ED fansite kit
(17.7MB) contains some background for DD and a novella covering most of the events between DD and BD.