Ancient Greek cities polities display a considerable variety of forms. In the realm of political philosophy, thinkers perceived these forms through a schema of complicated differences and resemblances. On the same time, they expressed their deep concern as to how polities change, degenerate or gradually shift one to another, and were at pains to verify these phenomena through historical paradigms. These lectures aim at highlighting the most important aspects of the relevant literature, in association with its contemporary developments in economy, society, institutions and diplomacy.