GO! Is a series of beginner books that can be used for teaching or independent reading. The books are organized into 7 levels, which provide individual students with reading challenges that match his or her ability. In levels 1 and 2 the books are written using a repeated sentence structure, where only one or a few words are changed from sentence to sentence. In level 3 and up the sentence structure is more open, with more emphasis on the book’s storyline.