I would have rated this book higher if the graphical images of tree branch ends could have been made larger. They are a bit small on the ipod screen. They would probably represent well on the iPad screen. The information is nicely documented though it may take a person a while to get on understanding the classification system if they have not studied biology before. Its a nice thing to have along when doing leisurely trail hikes due to being able to fit in an iPod in a pocket. Pretty compact. Very kind for it to be presented for free. Thanks for that.