In a century replete with radical politics, final liberations, historical codas, and dreams of eternity, the shadowy figure of Louis-Auguste Blanqui, the constant revolutionary, wrote Eternity by the Stars in the last months of 1871 while incarcerated in Fort du Taureau, a marine cell of the English Channel. In the midst of contemplating his confinement, Blanqui devises a simple calculation in which the infinity of time is confronted with the finite number of possible events to suggest a most radical conclusion: every chain of events is bound to repeat itself eternally in space and time. Our...