Unearthing the Unknown Whitehead argues that it is Alfred North Whitehead’s recently published Harvard lectures, and not his books, that contain the truest record of the development of his philosophy, including the false starts and dead ends that the published works obscure. This development could previously only be inferred as taking place in the gaps between books. It thus calls for a complete reconsideration of Whitehead’s philosophical corpus. Joseph Petek critically evaluates the accuracy and reliability of the student accounts of Whitehead’s recently published Harvard lectures and then examines these notes, along with a number of previously unknown essays, in order to trace previously unknown aspects of Whitehead’s philosophy and the development of his thought. Additionally, neglected early letters between Whitehead and Bertrand Russell appear to reveal a precise point at which he began transitioning from his long career in mathematics to a new career in philosophy. Two previously undiscovered essays—“Religious Psychology of the Western Peoples” and “Freedom and Order”—display Whitehead’s concern for a creeping hyper-nationalism that is intensely relevant in today’s political climate, along with terminological experiments that stretch our conceptions of Whitehead’s philosophy in new directions.