Spinoza is generally recognized as one of the most important philosophers of the early modern period; less well known are his observations regarding private ethical conduct, social control including state intervention in the market, and public policy including welfare. This book explores these political economy dimensions of Spinoza's thought setting them in the context of his own wider work and the broader intellectual history landscape. The discussion in the book takes account of Spinoza's relation with his contemporary Thomas Hobbes regarding constitutional matters as well as public policy; compares his stance respecting ethical conduct with that of Immanuel Kant, who came a century later, and with utilitarianism; and examines the objections to Spinozan doctrine by the seventeenth-century philosopher Pierre Bayle and thereafter by David Hume, and the nineteenth-century critics G.W.F. Hegel and J.S. Mill. More specifically, this book points to a hitherto unnoticed adjustment by Spinoza himself to his contrast between 'substance' and 'mode' thereby weakening the foundations of his philosophical-theological position. It also demonstrates the on-going relevance in civil society of the State of Nature for both Hobbes and Spinoza and underscores a divergence from Kant regarding private ethical conduct. The book also explores Spinoza's position on public policy, with emphasis on working-class welfare, a matter displaying a typically 'mercantilist' stance. The book will be of great interest to readers of the histories of political economy, philosophy, and political science in particular, and intellectual history more broadly.