Lee Allison, state geologist for Arizona and head of the AZGS, mentioned earlier today that the AZGS had uploaded their first book to the Kindle store.
The book is A Guide to the Geology of Catalina State Park and the Western Santa Catalina Mountains, and it's selling for $2. And as you can guess from the title and the publisher, this ebook is a 56 page guide to the geology of one small part of Arizona.
This is only the first ebook that the AZGS plan to release; other titles from their Down to Earth series should be out shortly.
P.S. It was the acronym that caught my eye.