The essays in this collection have been written for Gerd Buchdahl, by colleagues, students and friends, and are self-standing pieces of original research which have as their main concern the metaphysics and philosophy of science of the seventeenth and eighteenth centuries. They focus on issues about the development of philosophical and scientific thought which are raised by or in the work of such as Bernoulli, Descartes, Galileo, Kant, Leibniz, Maclaurin, Priestly, Schelling, Vico. Apart from the initial bio-bibliographical piece and those by Robert Butts and Michael Power, they do not discuss Buchdahl or his ideas in any systematic, lengthy, or detailed way. But they are collected under a title which alludes to the book, Metaphysics and the Philosophy of Science: The Classical Origins, Descartes to Kant (1969), which is central in the corpus of his work, and deal with the period and some of the topics with which that book deals.