This may have been mentioned before, but it's worth mentioning again:

Centipede Press is publishing a book of Hannes Bok's artwork. It has a hefty price tag (250 USD, unless you'd prefer the Deluxe edition which goes for 2995 USD... and no, I didn't miss out a dot between the 29 and the 95!), and an introduction by Bradbury.

Details here:
http://centipedepress.com/art/hannesbok.html

The Centipede Press book looks very beautiful. For those lacking the means to purchase that book, I would point out that back in 1993, Underwood-Miller published A HANNES BOK TREASURY, in both unsigned trade paperback and hardcover, and in hardcover limited editions signed by the introducer...Mr. Ray Bradbury. Current prices for the Underwood-Miller book range from approximately $20 for the trade paperback to $450 for the lettered and signed limited hardcover edition. A list of the copies currently for sale on the Advanced Book Exchange website can be found by clicking on the link below.

http://www.abebooks.com/servle...k+Treasury&x=71&y=10