What is the best guidebook on Greece?

I am visiting Greece soon and spending more than a week on the island of Santorini. Can anyone who has traveled there with a guidebook make a recommendation for me?

For reference, I took Let’s Go Europe when I traveled around in college, Lonely Planet post-college for Asia and Footprint Guide to South America last year. I’m not really a Frommer’s or Fodor type of traveler. Thanks!