From the dialogues of his spiritual ancestor, Proclus, apart from the Republic, he recalled the Cratylus, Parmenides, Timaeus, the first Alcibiades, Philebus, Theaetetus, Sophist, Phaedrus, Phaedo, and sections of the Symposium - and perhaps Protagoras, Gorgias, and the Laws. Many of these notes are not preserved and others have a partial character with respect to the discussed treatise.
The "Republic" is the dialogue that served as a central reference point for Plato's work. According to the subtitle's specifications, its subject is "about justice" and is defined as a "political" dialogue (issues for which Proclus has many notes in his Memoir). It may be the most comprehensive conception of the philosopher's mind, where his high ideas are exposed in a very broad thematic range, but mainly on ethical issues. This is why the Republic is taken as the forest guide for the principles of Platonic ethics, just as Timaeus serves for physics and Parmenides for dialectic. [...]

(from the introduction of the book)