This work aims to present the theses regarding the concept of good defended by George Edward Moore in the first chapter of his Principia Ethica (1903), a classic that is considered the founding book of metaethics as an area of study in Ethics. The second objective is to comment on its reception in Analytical Philosophy of recent decades. Moore defends, essentially, two theses in his first chapter of Principia: a metaphysical one, which concerns the good as non-natural; and an epistemological one, which defends ethical intuition as a means of knowing it. According to Moore, good is the only moral property, which certain things share in different ways, their character being simple, of unnatural order and indefinable. To substantiate this idea, he presents the famous open question argument and characterizes the naturalistic fallacy. Regardless of how much his theory is successful, which remains a controversy among experts, Moore demonstrated and ensured something crucial: the autonomy of Ethics in relation to empirical sciences, which this work also addresses. Following the presentation of Moore s theses, the article analyzes objections and readings from more recent commentators, such as Darlei Dall Agnol, Judith Jarvis Thomson, Peter Railton, among others, rescuing Moore s metaethics with an updated view.