This document is the contents page and introduction for the fourth edition of the book "Essential Grammar in Use" by Raymond Murphy. It provides an overview of the book's structure and contents. The book contains 115 units on different topics in English grammar. It is intended as a self-study reference and practice book for elementary learners of English. It encourages students to choose which units to study based on their individual needs, and provides exercises, answers keys and additional resources to aid independent learning.