These guides are like the Lunar ones, well I could be wrong on this one, but what I mean is they are like very fancy and they are like collectors editions quality, with very good print and page quality. Very nice ink work/paintings.
So I can understand why they could go for 50% more then what they are normally worth. I'm betting it has a LOT of pages too.
It has 400 pages, it's a heavy book with a nice hardcover.