The History of Western Philosophy (Book One): Ancient Philosophy is a monumental work by the famous British writer and philosopher Bertrand Russell, which takes the reader on a journey through the philosophical ages since the first beginnings in ancient Greek civilization. Russell defines philosophy as a means that combines theology and science, as it is based on contemplation of topics that remain scientifically unconfirmed, but also based on reason and logical thinking. In this book, Russell divides the history of ancient Greek philosophy into three main stages. The first stage begins with the Pre-Socratics, introducing classical philosophers such as Pythagoras, Heraclitus, and Parmenides. Then he moves to the second stage, which represents the golden age of philosophy with Socrates, Plato, and Aristotle, where philosophy is completed and reaches its peak. Finally, it deals with the third stage that begins after Aristotle, in which the Cynic, Epicurean, and Stoic schools develop.