This is the first of two split volumes of Classics of Philosophy, an anthology intended for introduction to philosophy and history courses and any reader interested in philosophy. It covers ancient and medieval philosophy from Thales to William of Ockham, including twenty-nine works by thirteen philosophers in addition to fragments from the Presocratics. The book strongly features the works of Plato (with the complete text of The Republic), Aristotle, and Aquinas. The editor has written introductions to each of the philosophers presented.