Diogenes Laertius

Ancient Greek writer whose Lives and Opinions of Eminent Philosophers is the primary source for the lives and doctrines of most ancient Greek philosophers — the only surviving ancient collection of philosophical biography — despite being criticized for accuracy.

Preserved more information about the ancient philosophical schools than any other source — without Diogenes Laertius, we would know far less about Zeno, Chrysippus, Epicurus, and dozens of others — making him indispensable despite being unreliable.