He also has "Maui revealed" which I bought for our trip last year, it was very informative, it listed some of the waterfalls during the trip to Hana which were really not known except to the people whom we encountered and they all had his book. That was so funny, we joked about it.
Also, once you have the book, you can check his website, just log in the code# which is listed in the book for additional information.
I think his books are a must if you visit Hawaii.