Diogenes Laertius lived probably in the earlier half of the 3rd century CE, his ancestry and birthplace being unknown. His history, in ten books, is divided unscientifically into two 'Successions' or sections: 'Ionian' from Anaximander to Theophrastus and Chrysippus, including the Socratic schools; 'Italian' from Pythagoras to Epicurus, including the Eleatics and sceptics. It is a very valuable collection of quotations and facts.
The Loeb Classical Library edition of Diogenes Laertius is in two volumes.