The Art of Ralph McQuarrie
Really nice coffee-table art book from an
independent publisher. In case you didn't know, Ralph McQuarrie is the guy who did all the production paintings for the original
Star Wars films. This book has a selection of stuff from his entire career, though, not just that trilogy.
McQuarrie is a meticulous craftsman; the book has loads of examples of cases where he'd do a production painting featuring a certain ship or character design, for instance, and then repaint the whole thing after the modelmakers altered the ship's look, or the makeup people changed the design.
Especially of note in this respect are his paintings of the early Millennium Falcon.
Here's an example. (That particular painting, sadly, didn't make it into the final book, but it can be seen in the recently-published volume
The Making of Star Wars, which is refreshingly unbiased in its narrative of the first film's evolution.)