A practical, easily accessible guide for bench-top chemists, this book focuses on accurately applying computational chemistry techniques to everyday chemistry problems. It provides nonmathematical explanations of advanced topics in computational chemistry. It focuses on when and how to apply different computational techniques. It addresses computational chemistry connections to biochemical systems and polymers. It provides a prioritized list of methods for attacking difficult computational chemistry problems, and compares advantages and disadvantages of various approximation techniques. It describes how the choice of methods of software affects requirements for computer memory and processing time.