Longman Guide to English Usage by Sidney Greenbaum
This is a practical guide to difficult and disputed points in modern English, both written and spoken. Containing 500 entries it covers a range of language problems in meaning, grammar, spelling, pronunciation, punctuation and style etc providing advice which reflects up-to-date standards and uses. The items are arranged in single alphabetical sequence and are cross-referenced and contain numerous examples of modern usage. The authors have also written an edition of Gowers' "Complete Plain Words".