Raymond Murphy's "English Grammar in Use" is the first choice for intermediate (B1-B2) learners and covers all the grammar you will need at this level. This book has clear explanations and practice exercises that have helped millions of people around the world improve their English. It also includes an interactive ebook with audio that you can use online or download to your iPad or Android tablet. It is perfect for self-study and can also be used by teachers as a supplementary book in classrooms.