Basic grammar in use fourth edition is an american english self-study reference and practice book for beginner level learners (a1-b1). With simple explanations, clear examples, and easy to understand exercises, it is perfect for students who are learning on their own, but can also be used in the classroom. Inside the book is a code for an ebook. The ebook works on pcs, macs, iPads and android tablets. It has the same grammar explanations and exercises found in the printed book, plus other great features such as audio for all the example sentences and an easy to use answer key.