With meticulous scholarship and an accurate, highly readable translation, this volume sheds light not only on Spinoza's debt to Descartes but also on the development of Spinoza's own thought. Appearing for the first time in English translation, Lodewijk Meyer's inaugural dissertation on matter (1683)--relevant for its comments on Descartes, Spinoza, and other thinkers of the time--is appended with notes and a short commentary. Cross-references to Descartes's Principles of Philosophy are provided in an index, and there is an extensive bibliography.