Al is 100% dead on with this. I buy a lot of books, mostly military artwork books and also wargaming rules sets, I do not for the most part buy any books blind, there are a few I've bought sight unseen, but most require a quick look through.
At the recent wargaming show I attended, I had 5 books on my shopping list and once I had a chance to look through them, I pulled the trigger on just one of them, the other 4 did nothing for me.
Without a guy like Dennis from OMM, this would not be possible; if he weren't around, not sure what I'd do as far as book buying. His prices are not bend over bargain basement prices like Amazon, but he provides great customer service and to me, that far outweights saving a few dollars on a book.
Sometimes price is not and should not be a hot button; once all the mom and pop book dealers are gone, guys like me are going to be sorry..................