Diogenes of Laertius in Cilicia (first half of the 3rd century AD), an Athenian grammarian, left us the only “history of philosophy” written in antiquity—10 books setting forth the teachings of ancient Greek thinkers, beginning with the Seven Sages and ending with the Stoic and Epicurean schools. His treatise is a most curious and fascinating ancient mixture of the important and the unimportant, the primary and the secondary, the serious and the amusing. Thanks to this, the modern reader can plunge into the boundless sea of ancient thought and “breathe the air” of genuine ancient civilization.