Otto Jespersen 
Essentials of English Grammar [PDF ebook] 
25th impression, 1987

First Published in 2004. A classic of English grammar, Essentials of English Grammar provides a common ground for the traditionalist and the structural or descriptive linguist. Jespersen’s work provides insight into the fundamental concepts that underlie the linguistic approach, but at the same time the foundation of the traditional approach is retained. grammar, giving the student a real insight into the structure of the language. Grammatical rules are laid out in a clear, concise way and are illustrated with carefully selected examples.