Abstract
Anaximander wrote a book which was catalogued by the librarians of Alexandria under the title Πέρι Φύσεως--the first of many books so called. It is the first known philosophical work, in fact the first known prose work, in Greek. Of this book only one sentence is extant: "Into that from which beings have their origin they also have their passing away, by necessity; for they render to each other retribution and atonement for their injustice in the order of time." But numerous references from reliable ancient sources enable us to recon- struct, with reasonable certainty, some of the principles of his doctrine.