In Aristotle's view, Anaxagoras stood out from the other Presocratics as a sober man among the incoherent. This book explores the fragmentary evidence both for Anaxagoras's concept of mind - to which Aristotle was particularly referring - and for his subtle, complex and elusive theory of matter and change. It is concerned with two aspects of his writing in particular: its comparativelt high ratio of dogmatic assertion to argument, and a pervasive ambiguity or indeterminacy in the presentation of Anaxagoras's philosophical theses. The problems posed by Anaxagoras's work are examined not only by means of philosophical comparison with what survives of other Presocratics, but in the light of the development of the prose book as a vehicle for the communication of ideas in early Greece. A book for the scholar of ancient philosophy.