This text is inspired by one of the most enigmatic and provocative topics of the modern Platonic studies, viz. by the so-called unwritten, or oral, doctrine of Plato. We are focusing on two texts: one of them is Aristotle’s work On the Good, reconstructed on the basis of various testimonies from later doxography and commentaries, which apparently represents a synopsis of the homonymous lecture delivered by Plato at his school, and constitutes one of the most important sources for those who support the theory of the Unwritten, or Oral, doctrine of Plato; the other text is Plato’s Republic, or rather a number of its relevant contexts. Obviously, there is substantial difference in terminology and concepts between the dialogues (except for a few, including Philebus) and the theses articulated in this Aristotle’s synopsis. Nevertheless, the authors hold that the form and structure of Plato’s written dialogues on close reading make up a unique language of Plato’s philosophy. There is no reason to oppose Plato as the author of dialogues and Plato as the author of the lecture On the Good. The composition of the dialogues, specifically the Republic, is highly revealing,allowing to perceive, e.g., that Plato’s mathematical discourse takes us to a lower level of his philosophizing, and is exploited as a propaedeutical strategy.