This book provides a detailed review of statistical tools used in analyzing and addressing environmental issues. It examines commonly used techniques found in USEPA guidelines and discusses their potential impact on decision-making. The authors are not constrained by statistical formalism; they advise when to go outside of standard statistical models when making difficult decisions. The content is presented in an practical style that emphasizes methods that work, based upon the authors' extensive experience. It also emphasizes the exact question that each procedure addresses, so that readers can clearly identify the question they want to ask and correctly interpret the results.