Book excerpt: A 107 mile ribbon of highway spans the line green waters and more than 200 islands the comprise the florida keys. Just offshore, a necklace of dive sites parallels the archipelago. Divers have easy access to the shallow reefs and spectacular wrecks, such as the Adolphus Bush Sr. or the U.S. Coast Guard cutters Duane and Bibb. Visitors to the keys can swim with lodge. This book describes 61 of the best sites in the region, from Biscayne Bay to the dry tortugas, with full color photos throughout.