`We are all Greeks. Our laws, our literature, our religion, our arts, have their root in Greece', the poet Percy Bysshe Shelley once wrote. It is in Greek that the questions which shaped the destiny of Western culture were asked, and so were the first attempts at an answer, and the search for a method of investigation. This book tries to rediscover the propulsive force that for over two millennia spread, and still lives in our system of thought. By systematically quoting the very words of the leading actors and by tracing their sources, it leads the reader along a path where they will be able to observe the establishment of philosophical ideas and language, in an updated and balanced picture of archaic lore, of the thought of the classical and hellenistic ages, and of the philosophy of late antiquity. The book looks closely at the progress of scientific thought and at its increasing autonomy, while following the evolution of the fruitful yet problematic relationship between the Greek world and the Near East.