The Guardian is tracking the prices for art books. Helmut Newton’s Sumo went for $430,000:

In 1999 Benedikt Taschen published Sumo, a retrospective of iconic photographer Helmut Newton. The monograph, complete with a Philippe Starck display stand, was the largest book produced in the 20th century. Measuring in at 50cm by 70cm, the German publisher had to call upon the Vatican’s bible binder to help make it. The 10,000 copies sold at a staggering £6,000 each, while the first of the limited run, signed by 80 of the celebrities shot by Newton, later sold at auction for $430,000. Now, copies of Sumo often pop up on eBay – one recently sold for $15,000.

Taschen explains why he thinks his books are gaining in value as the overall price of books–new and used–declines across the board:

This pricing might seem wildly inappropriate to the average punter, but it’s an industry representing a sea change in questioning what is and isn’t desirable or considered a work of art. As Taschen says, “most art lovers are, by their nature, interested in new ideas or groundbreaking projects, so why not present those to them in the form of a book”? Why not, indeed. They may not hang, framed, from the wall, but the consensus suggests that these luxury, limited-edition books become artworks in their own right.

Are Luxury Photography Books Recession-Proof? (Guardian)