Richard Sylvan (né Routley) was Senior Research Fellow in the Philosophy Programs at the Austra- lian National University, where he linked the 'deep-green' theory of environmental philosophy for which he is most widely known to an astonishing range of work in metaphysics, semantics, logic and value theory. He died suddenly in 1996 at the age of 60, when he had just completed this major text. But though this volume is the mature expression of one of our foremost modem philosophers, it remains, like all his work, pioneering, eclectic and controversial.Sylvan's theory of 'plurallism', the culmination of his life's work, is the subject of this important text. In his own characteristically provocative words 'There is not merely a plurality of correct theories and more or less satisfactory worldviews: there is a corresponding plurality of actual worlds. Plurality penetrates deeper in full plurallism than linguistic surface or than conceptual or theoretical structure, to worlds... There is no single fact of the matter, there are facts and matters.'