Got some bad news for you. Many of the Escher web sites have been
greatly scaled down, or pulled altogether. It seems that the company that
owns many of the copyrights to Escher's work have come out with a CD-ROM of
his work....and have threatened those with Escher works on their sites with
law suits! Apparently they felt that these sites would detract from their
sales. Go to Yahoo and do a search...you'll find some sites with info on his
life, but not much else....
I ended up buying a 1998 calendar of his work to show my classes. They
love his tesselations!