The volume provides for the first time in scholarship a comprehensive and in-depth analysis of the relationship between Stoicism and early Greek philosophy, from Orphism to the Monists and the Pluralists. Going beyond the common assumption that the Stoics refer exclusively to Heraclitus, it is shown that almost the entire Presocratic tradition (sometimes mediated decisively by Plato and Aristotle) has made a fundamental contribution to the construction of Stoic thought, especially in the field of physics (i.e. cosmology, ontology, and theology).