W.K.C. Guthrie 
Greek Philosophers [PDF ebook] 
From Thales to Aristotle

W.K.C. Guthrie has written a survey of the great age of Greek philosophy – from Thales to Aristotle – which combines comprehensiveness with brevity. Without pre-supposing a knowledge of Greek or the Classics, he sets out to explain the ideas of Plato and Aristotle in the light of their predecessors rather than their successors, and to describe the characteristic features of the Greek way of thinking and outlook on the world. Thus The Greek Philosophers provides excellent background material for the general reader – as well as providing a firm basis for specialist studies.