Thirteen original essays by leading scholars explore aspects of Spinoza's ethical theory and, in doing so, deepen our understanding of the richly rewarding core of his system. Given its importance to his philosophical ambitions, it is surprising that his ethics has, until recently, received relatively little scholarly attention. Anglophone philosophy has tended to focus on Spinoza's contribution to metaphysics and epistemology, while philosophy in continental Europe has tended to show greater interest in his political philosophy. This tendency is problematic not only because it overlooks a central part of Spinoza's project, but also because it threatens to present a distorted picture of his philosophy. Moreover, Spinoza's ethics, like other branches of his philosophy, is complex, difficult, and, at times, paradoxical. The essays in this volume advance our understanding of his ethics and also help us to appreciate it as the centerpiece of his system. In addition to resolving interpretive difficulties and advancing longstanding debates, these essays point the direction for future research. Spinoza's enduring contribution to the development of ethical theory, to early modern philosophy, and indeed to early modern history generally, provide us with good reason to follow the lead of these essays.