Since the rise of modern thought and natural science, teleological discourses have been banished as explanatory tools in natural investigations. The various contributions to this volume embrace the task of rethinking natural purposiveness in accordance with natural science. They set out from the issue of whether, and in which form, it is possible to talk of purposes in nature, without resorting to an account requesting some intentional agent. The legitimacy of such a notion as that of internal teleology has been addressed, together with the issue of what the term "internal" properly denotes. It is meant to be an alternative both to the position of those who assume that teleology in biology requires a dimension transcending nature itself and find in teleological language an argument for the Intelligent Designer, and to the stance of those who aim to eliminate teleology from scientific inquiry altogether.