There are some books in the game that just contain images (see
Art of Divine Divinity). In the starting cell block, you can find a manuscript with the image of a sand demon, for example. Some of these also have runes on them, which can be translated; the
Beyond Divinity Strategy Guide contains a chart of which Rivellon and Raanaar runes correspond to which letter (it should be in the forum somewhere, as well, but I can't seem to find it...). Nothing important is written in runes, though, so it isn't necessary to do any manual translating (one of the artists working on DD put his web site URL on an image in runes).
There are also books in the Raanaar language which will be automatically translated after you find 3 books located throughout the game, which 'teach' you the language.
