The very fact that you are reading this preface indicates that you will be taking (or are taking) a course in general chemistry. This guide is suitable for a college level general chemistry course as well as a high school chemistry course, especially AP Chemistry. It is also designed to assist someone in reviewing basic chemistry principles in preparing for a professional exam, proficiency exam, or the like. Both of us have many years of experience in teaching introductory general chemistry at the university level, but each of us has certain skills and experiences that will be of special help in the presentation of the chemistry material in this book. Richard “Doc” Langley has taught high school chemistry and has been a grader for the AP Exam chemistry free-response questions for years. John Moore has years of experience teaching chemistry to both public school teachers and students and is the author of Chemistry for Dummies. We are also the coauthors of 5 Steps to a 5: AP Chemistry. We have tried to present the material in such a way that it is understandable and to provide you with some hints and tips to make your studying and learning the material more effective. Use this book in addition to your regular chemistry text. In several places we will refer you to your text for tables, and so on, that were too extensive to put in this book. We have tried to concentrate on those topics that we find most students have trouble. Pay particular attention to the Utterly Confused About … section of each chapter. These topics are the ones that we find are the most difficult for students to master. The Test Yourself section will give you an opportunity to see if you understand the concepts and should point out your weak spots for additional study. You will have to work and study hard to do well, but we are confident that this book will help you master the material and lift that fog of confusion.