This is a free online book you can use. It is a little difficult to sign up because you have to sign up twice, once for the book and once for the app that you read it on. The app can also be useful for other books to read too. Click the pictures below to investigate more if you like.
If you really are interested in using a book on you tablet or on-line, which I recommend, because they are free and better then your stupid book ( did I every tell you before that I think it is stupid?) I still recommend this one below and in fact I insist on using it in class in the future anyway.