Long-standing theories about Whitehead's early philosophical efforts can now be challenged or overturned. In this volume, leading Whitehead scholars address the ways in which the 1925-1927 Harvard lectures challenge or confirm previous understanding of Whitehead's published works, trace the development of Whitehead's thought in the crucial period after Science and the Modern World but before Process and Reality, examine Whitehead's singular guest lecture in Richard Clarke Cabot's seminar in social ethics a topic which Whitehead usually avoided and elucidate how these lectures be seen as a bridge between his mathematical and philosophical work.