The Nicomachean Ethics is Aristotle's chief work on ethics, and one of the most important of his surviving philosophical works.
The book's modern name reflects a tradition that it was either dedicated to or even edited by Aristotle's son Nicomachus; there is no mention of or evidence for this in the text itself. Nicomachus was also Aristotle's student, and his successor as head of the Lyceum, which makes it credible if not likely that he had some influence over the form and publishing of his father's works.
The other two Aristotelian works on ethics are the Magna Moralia (now widely agreed not to have been written by Aristotle himself, though it may contain notes made one of his students) and the Eudemian Ethics (generally agreed to be an authentic work by Aristotle, and usually thought to be earlier than the Nicomachean Ethics[1]).
Both the Eudemian Ethics and the Nicomachean Ethics are essentially collections of notes rather than polished works, though it is not known whether they were written as aids to lecturing or as records of his lectures and discussions. Of the ten books of the Nicomachean Ethics and the seven of the Eudemian Ethics, three are shared (books 5–7 of the former, books 4–6 of the latter). It is not known for cerain why this is the case, though the generally accepted view is that they originally appeared in the earlier Eudemian Ethics and were used to fill gaps in the later work, either because Aristotle left it unfinished or (more probably) because parts of it were lost.