Google Play is giving away a free book today "Android Photography" Did not have time to look at it yet but I just couldn't pass up the price. 
https://play.google.com/store/books...nid=20130711_EM_US_AndroidPhotoBook_A_HeroCTA
https://play.google.com/store/books...nid=20130711_EM_US_AndroidPhotoBook_A_HeroCTA