Cardshark is a blast of a book. The skill level ranges from "advanced-beginner" to "If I practiced for a million years, I still couldnt pull it off."
In my opinion, of Darwin's three major books for magicians (including "Darwin Ortiz at the Card Table" and "Scams & Fantasies") this one had the most commercial routines, especially for those of us who dont adopt the Gambler persona. "Blindfold Aces" has paid for the book many times over, and now that I've told you about it, forget I said anything. Just rip those pages out of the book when you get it.