The mastery of a language entails the knowledge of both its grammatical and communicative competence. Presently, in Nigeria, hardly do learners and their tutors distinguish the various contexts of usage. This is because they do not seem to understand what expression is appropriate in what situation. Their spoken English appears so rigid and pedantic that one might think that the speaker has been talking to only one person, about one subject in all situations of her/his life. Moreover, most speakers do not distinguish between formal and informal situations, between different audiences, between topics, purposes and other crucial factors that determine appropriate choices of words and expressions when speaking.In this introductory book, we try to examine and explicate the grammar of the English language in a manner that makes it easy for learners and tutors to comprehend, explore and master.