ABSTRACT
The texts of ancient philosophy, like ancient literature in general, have survived only to a limited extent. For the most part they are not preserved in their original form, but only by means of citations and abstracts that were made by others, who either quoted or paraphrased the original works, or were themselves dependent on anthologies or other intermediate writings and reports. The Presocratics took into account what other people, especially other philosophers, had said, in both a critical and a creative sense. This they were also able to do because books had begun to circulate. Heraclitus criticised the poets Homer and Hesiod, but also the philosophers Xenophanes and Pythagoras. An important novelty in Diels' book was the reconstruction of a doxographical treatise that has proved to be of fundamental importance for the history and historiography of Greek philosophy.
