In the fourth and final volume in his Age of Unreason series, Keyes brings his multi-threaded yarn to a thrilling conclusion. Based on the premise that Sir Isaac Newton devised a theory of alchemy that led to the industrial use of demons, the book builds to a climactic confrontation to see who will reshape the universe. Keyes entertains both with details of everyday life and with the conversations of people who may not have met but should have. He produces a fine pastiche of the formal writing of Voltaire (who appears as Franklin's friend and rival), marred only by a more modern 'crash cut' narrative, which occasionally jumps mid-scene or reverses chronology, diffusing the suspense. Still, with the unfolding of secrets and past deeds, Keyes brings a welcome level of character uncertainty to the deterministic Newtonian novel.