This document provides an introduction to Grammar Essentials, a book that aims to help readers improve their writing skills. It discusses how to effectively use the book over 20 chapters that can each be completed in 20 minutes. The introduction explains that writing allows for revision, forces clarification of thoughts, and creates a lasting record. It notes some key differences between spoken and written English, advising that informal language, wordiness, sudden subject changes, abbreviations, and symbols are generally not appropriate for formal written communication. The introduction provides context and guidance for how to study the book and writing concepts covered.