An excellent guide to the English language, is THE specialist in the matter, Michael Swan. The English language as it is really used ... today. Grammar, but also points vocabulary, style, pronunciation and spelling, as well as idioms. Not to mention the correspondence, and the main differences between British English and American English. In my opinion, the best book on the subject. A very thorough analysis, with an excellent index to quickly find what you are looking for. Maybe a bit expensive, but worth every penny! Recommend for any student not only the language, but even for teachers: a quick and clear explanation ... a language that is sometimes complex and difficult to explain to others.
