A grammar reference and practice book for learners of English at advanced (CEFR C1-C2) level. Perfect for self-study, but also ideal for supplementary activities in the classroom. This fourth edition is the highest level in a series that has been used by millions of language learners and teachers around the world. It contains 105 units, including five new units on grammar for academic purposes. Online resources are also included: a 36-month subscription to the eBook version with audio and answer keys, plus over 200 quick, Online Tests to check understanding and get feedback on grammar points needing further study.