Bradt Azores by David Sayers (2004, Paperback)

There aren't many travel guides specifically for the Azores, an off the beaten track place. Most guides slip a small amount of information in the portugal travel guides, however, if you are going to the Azores, you are probably just going to the Azores. this is the most excellent travel guide i have seen giving the most detailed data per island. There are numerous color pictures and excellent maps.