If we were to ask Michelangelo why we look the way we do, he would answer that this is primarily due to the action of our soul upon our body. In other words, he would say that it is our soul, or the intellective part of it, that makes us human and organizes and beautifies our body accordingly. This essay shows how these beliefs come from a number of sources that were of upmost importance to the great sculptor, such as Plato and Aristotle, but also Dante, Petrarch, Girolamo Savonarola, Marsilio Ficino.After reviewing the rich tradition that led Michelangelo and most of his contemporaries to think that a man's soul can be "seen" in his body, the book turnes to the relevant beliefs of some more recent authors about some of whose ideas concerning the human soul Michelangelo is likely to have read or heard. In the end, we find a discussion of those famous works that most seem to evoke a sense of "soul" or "inner being" in viewers today.