The book of Professor A.F. Losev contains a philosophical and philological analysis of the treatise of the Greek writer of the 3rd century AD Diogenes Laërtius. His treatise is the only consolidated work of the ancient era that has come down to us, which contains biographical information about all famous ancient Greek philosophers and sets out their teachings. The author of the book shows the features of the literary manner of Diogenes Laertius, criticizes unscientific approaches to assessing his work, gives an integral artistic and cultural-historical characteristic of this most interesting writer.