The concepts of time and identity seem at once unproblematic and frustratingly difficult. Time is an intricate part of our experience -- it would seem that the passage of time is a prerequisite for having any experience at all -- and yet recalcitrant questions about time remain. Is time real? Does time flow? Do past and future moments exist? Philosophers face similarly stubborn questions about identity, particularly about the persistence of identical entities through change. Indeed, questions about the metaphysics of persistence take on many of the complexities inherent in philosophical...