Practical English Usage has sold over 2 million copies worldwide. Now revised and updated for the fourth edition, it answers the questions that teachers and learners ask about English grammar and vocabulary with clear, corpus-informed explanations and examples. Completely revised and updated to reflect changes in language use. NEW Organisation into two easy-to-use parts, making it quicker to find the information you want. Part 1 is a complete topic-by-topic student's grammar, with section introductions highlighting common mistakes. Part 2 is a guide to key vocabulary topics, including an A-Z list of common word problems. NEW Also available online, including 87 diagnostic tests.