Book excerpt: REA’s Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Logic covers the basic concepts of logic, including sentences, arguments, and the evaluation of arguments. This book will give the reader a clear understanding of sentence logic such as symbolization, semantics, and truth trees by giving concise definitions and examples of each.