The WordMonsters: Learn to Read is an excellent decodable book series. Multiple books for Kindergarten and 1st grade present high frequency words, focused phonics practice and interesting stories with hot spot interactivity to support kids learning to read. Help comes when ever you need: by tapping a word, from a resourceful robot pal built into the app or through the free online and printable support materials designed for adults. After working through each decodable book, enter the activities page to check on comprehension and play with words and sounds. The series is built around in-app purchases so you can purchase exactly what you need. Currently there are a handful of books, but more will be added to complete a series of 24 books.