The book was written by a local and to the best of my knowledge it's only avalible on island. I am going back in June, be happy to pick one up for you. I don't want to make a bigger deal of this than it really is but the biggest "tip" I can give is how to avoid petty crime. There are some kids that will steal valuble items if you leave them in vehicles. The prevention is easy if you simply don't take anything with you to remote sites that's worth stealing. If you are not taking it in the water with you, leave it at the hotel. DON'T take or leave cameras, expensive sun glasses and the like in the car. LEAVE THE CAR UNLOCKED and the windows down. Old tennis shoes and T-shirts are safe and coolers are never taken....you may loose a drink or 2 so carry extras (although I have never lost any, I have heard of some who have)The island is small so it's just not necessary to carry a lot of stuff with you. Your never more than a few miles away from your hotel anyway. I take a credit card and $50 or so, all of which goes in the water with me. My camera is an UW one so it goes under too. We have found that a thin dive cap, 1/8 inch or so, helps a lot. While the water is 80 deg+ it still takes a toll on us after 3 to 4 dives and the cap seems to help reduce fatigue a lot esp after several dives. Nylon dive skins are useful to prevent sunburn and shield against jellyfish and coral stings. I am unaware of any big walls but I understand that there are some small ones tward the northern end of the island. Matter of fact, the underwater web cam is located at a site called "Small Wall". There seveal ATM's on the island that you can get money from, either in Guilders or USD. By the way, the exchange rate is 1.77 and is fixed to the USD. This works out to 1 Guilder= about $0.56 US but I usally use $0.50 USD = 1 Guilder for estimation. A 10 Guilder hamburger is a little over $5 US. I can't wait to get back myself, I love the place in case you couldn't tell.