This book tells an overlooked story in the history of ideas, a drama of cut-throat politics and philosophy of mind. For it is Cicero, statesman and philosopher, who gives shape to the notion of will in Western thought, from criminal will to moral willpower and 'the will of the people'. In a single word – voluntas – he brings Roman law in contact with Greek ideas, chief among them Plato's claim that a rational elite must rule. When the republic falls to Caesarism, Cicero turns his political argument inward: Will is a force in the soul to win the virtue lost on the battlefield, the mark of inner freedom in an unfree age. Though this constitutional vision failed in his own time, Cicero's ideals of popular sovereignty and rational elitism have shaped and fractured the modern world – and Ciceronian creativity may yet save it.