Thomas Holden presents a fascinating study of theories of the structure and internal architecture of matter in the seventeenth and eighteenth centuries. Are the parts of material bodies actual or potential entities? Is matter infinitely divisible? Do all material bodies resolve to actual first parts? All the great philosophers and philosopher-scientists of the period address these issues, including Galileo, Descartes, Newton, Hume, and Kant. Holden offers a brilliant synthesis of these discussions and his own overarching interpretation of the debate. "This book is a very well researched, clearly written, and thought-provoking examination of what the internal structure of physically extneded bodies was thought to be by Western scientists and philosophers in the 17th and 18th centuries...Because of the author's interpretive perspective the book has the virtue of viewing the origins of modern science from an ontological perspective..."--Notre Dame Philosophical Reviews "Holden has made an important contribution. His aim of locating every major natural philosopher of the period within the gridwork of an original classificatory system is fully realized. The book is an unqualified success in showing how Kant's problems in the late eighteenth century are continuous with Galileo's problems in the early seventeenth."--Catherine Wilson, British Journal for the History of Philosophy A fascinating study of theories of the structure and internal architecture of matter in the seventeenth and eighteenth centuries. Thomas Holden is in the Department of Philosophy at Syracuse University.