"You shall not lie!" - Moral statements typically do not pose any problems for us in everyday life. However, upon closer examination, they raise a variety of questions that the philosophical discipline of metaethics has been addressing since the early 20th century. Are these statements capable of being true, or must they be interpreted as purely subjective expressions of feeling? Are there moral facts that such statements refer to, and if so, what are their nature? This volume gathers central texts of metaethics, including works by George Edward Moore, Richard Hare, John Leslie Mackie, Bernard Williams, and John McDowell. It traces the semantic, epistemological, ontological, and motivational debates of recent decades and provides insight into current controversies.