The Nicomachean Ethics, written by Aristotle, represents his most important contribution to the field of ethics; This is a collection of ten books, covering a variety of interesting topics, throughout the collection. Aristotle attempts to derive a general understanding of the human good, exploring the causes of human actions, trying to identify the most common ultimate goal of human actions. Indeed, Aristotelian ethics also explores through the psychological and spiritual realms of human beings. Without pretending to exhaust ourselves with too many references, it would rather be useful to focus on the most criticized part of the philosopher's attempt, which is also the very beginning point of his masterpiece, identified as eudaimonia (happiness, well-being) and ergon (function), in Aristotelian terms. The meaning of eudaimonia, etymologically, is “good spirit” and it is usually translated as “happiness”; in Aristotelian terms, “happiness” represents the highest human good and it is also the representation of the virtues of the soul. The identification of the parts of the soul as contributors and principal elements for the functioning of the most important human activity (reasoning), marks the inevitable psychological trump card of Aristotle's thought; more precisely, the classification of human virtues arises from the analysis of soul types, attributing to human beings the capacity to reason which distinguishes them from the rest of "natural bodies". Indeed, reason exists in two parts of the soul, namely the rational and the appetitive (desires or passions), and it thus expresses within two different virtues, the moral and the intellectual. The moral virtues satisfy the impulses of the appetitive part and the intellectual virtues have...... middle of article......tp://classics.mit.edu/Aristotle/nicomachaen.html.Kraut, R., (2014). Aristotle's ethics. The Stanford Encyclopedia of Philosophy (Spring 2014 edition), Edward N. Zalta (ed.) Available online at URL .Grant, S., (2007). A defense of Aristotle on the good life. Richmond Journal of Philosophy (16) p. 1-8.Hesse, H., (1930, 1957) Narcissus and Goldmund. Montagnola, Picador, New York. Korsgaadar, C.M., (1986). Aristotle on function and virtue. History of Philosophy Quarterly, 3 (3), p. 259-279. Nagel, T., (1972). Aristotle on Eudaimonia. Phronesis, Vol. 17, no. 3, p. 252-259. Urmson, JO, (1988). Aristotle's Ethics (Blackwell), ch.1.Wilkes, KV, (1978). The good man and the good of man in Aristotle's ethics. Spirit 87; repr. in A. O. Rorty, ed., Essays on the Ethics of Aristotle (Berkeley, 1980).