The primary goal of this handbook is to familiarize adult English as a second language (adult ESL) instructors with the most important grammatical concepts and difficulties encountered by students in and out of the classroom while providing both novice and experienced instructors with the tools necessary to exemplify and explain, when necessary, such concepts in a clear and effective manner. By carefully reviewing the examples, explanations, and notes contained in this handbook, instructors will learn to employ the “natural” method (sometimes also referred to as the “direct” method) in their presentations of several of the most essential points of English grammar. While this handbook is not intended to provide an exhaustive review of English grammar, it does aim to address the most common sources of grammatical difficulty encountered by teachers and students in typical adult ESL settings. The examples presented throughout this handbook use Standard American English and cover a wide range of grammatical concepts at the beginning, intermediate, and advanced proficiency levels. This handbook emphasizes practical grammatical concepts, that is, issues mainly involving English morphology and syntax, along with some important lexical points. Upon completing their review of the material presented in this handbook, ESL instructors should be able to apply the natural method to their presentations of the most fundamental grammatical topics encountered in the classroom, across the proficiency levels and independent of theme-specific lesson content. Although this handbook does not presuppose any specific linguistic training on the part of the reader and technical linguistic jargon has been intentionally kept to a minimum, some basic linguistic terminology has been used out of necessity given the content of this work. Readers who are unfamiliar with basic linguistic concepts (such as morphology, syntax, lexicon, aspect, grammaticality, etc.) should be able to consult standard reference materials in order to resolve their uncertainties with a minimum of difficulty. The author has developed and revised this handbook over the course of many years of training novice and experienced instructors to teach a broad range of ESL curricula (including general, academic, and business English at all proficiency levels) to adult learners in diverse educational settings and instructional formats (such as private, one-on-one tutorials and multi-level intensive English programs taught in small and medium-sized groups). Each grammatical concept presented in this handbook is accompanied by numerous examples of realistic usage to aid the reader in understanding those concepts and to assist the instructor with his or her presentation of those grammatical concepts in the classroom. Finally, the reader should keep in mind that this handbook is practical rather than theoretical in nature and has been specifically designed to serve as a useful addition to the ESL instructor’s professional “tool kit.” It is the author’s hope that the reader will find this handbook to be easily approachable and highly relevant to the issues encountered during his or her daily instructional responsibilities.