"The Lives and Opinions of Eminent Philosophers"
by
Diogenes Laertius
is a famous work of ancient Greek literature, first written in the 3rd century CE. The book is a collection of biographical sketches and philosophical reflections about the lives, teachings, and sayings of various philosophers from ancient Greece, spanning from the Pre-Socratics to the Hellenistic period.
Diogenes Laertius' work is one of the most valuable sources for the history of ancient philosophy, as it preserves many details about the lives and ideas of philosophers that might otherwise have been lost. The text is divided into ten books, each dedicated to a particular philosophical school or figure. Though Diogenes often incorporates anecdotes, legends, and personal opinions, making the text as much a work of literature as of philosophy, it remains a key text for understanding ancient philosophical thought.