Do we desire things because they are good, or are they good because we desire them? Objectivists answer that we desire things because they are good; subjectivists answer that things are good because we desire them. Further, does it make sense to account for moral disagreement by claiming, as the moral relativist does, that something might be good for one person but not for another? Some essays in this book consider whether objective moral truths can be grounded in an understanding of the nature of human beings as rational and social animals. Some discuss the ethical theories of historical figures - Aristotle, Aquinas, or Kant - or offer critical assessments of the work of recent and contemporary theorists - such as Moore, Putnam, Ayn Rand, Philippa Foot, and Rosalind Hursthouse. Other essays ask whether moral principles and values can be constructed through a process of practical reasoning or deliberation.