The long history of ethics has had as its driving force the goal of establishing basic principles to govern human behavior and against which our actions can be judged and determinations of responsibility made. But as the twentieth century began, Moore believed that it was time to get back to basics and to ask the relevant questions once again. What is good? How do we define it? What do we mean when we call something 'good'? He contends that much of what serves as the foundation for ethics is in jeopardy - i.e., open to the "Naturalistic Fallacy" - because the question of defining "good" is not fully addressed. Here one of the most penetrating minds of modern philosophy seeks to clarify the fundamental elements of ethical discourse.