Spinoza's Political Psychology advances a novel, comprehensive interpretation of Spinoza's political writings, exploring how his analysis of psychology informs his arguments for democracy and toleration. Justin Steinberg shows how Spinoza's political method resembles the Renaissance civic humanism in its view of governance as an adaptive craft that requires psychological attunement. He examines the ways that Spinoza deploys this realist method in the service of empowerment, suggesting that the state can affectively reorient and thereby liberate its citizens, but only if it attends to their actual motivational and epistemic capacities. His book will interest a range of readers in Spinoza studies and the history of political thought, as well as readers working in contemporary political theory.