Lately it occurs to me what a long strange trip it's been
Nothing happens without friends.
I would like to thank my long friend Jonathan Smith for invaluable encouragement, guidance, and practical assistance.
I would like to thank the anonymous reviewer who pointed out that I was using time used in multiple senses in an earlier work.
I would like to thank John Cramer, Robert Forward, and Catherine Asaro for helpful conversations (and for writing some fine SF novels).
I would like to thank Linda Marie Kalb, Ferne Cohen Welsh, and Diane Dugan for their long and ongoing moral and practical support.
I would like to thank my brothers Graham and Gaylord Ashmead and my brother-in-law Steve Robinson for continued encouragement.
I would like to thank Connie Willis for several entertaining conversations about wormhole physics, closed causal loops and the like (and also for writing several fine SF stories).
I would like to thank Oz Fontecchio, Bruce Bloom, Shelley Handin, and Lee and Diane Weinstein for listening to a perhaps baroque take on free will and determinism.
I would like to acknowledge a considerable intellectual debt to Julian Barbour, Paul Nahin, Huw Price, L. S. Schulman, Victor J. Stenger, and Dieter Zeh.
I would like to thank Paul Nahin for some helpful email.
I would like to thank the librarians of Bryn Mawr College, Haverford College, and the University of Pennsylvania for their unflagging helpfulness.
I would like to thank countless other friends and acquaintances, not otherwise acknowledged, for listening to and often contributing to the ideas here.
I would like to thank John Myers and others at QUIST and DARPA for useful conversations.
I would like to thank the participants at the third Feynman festival for many good discussions, including Gary Bowson, Fred Herz, Y. S. Kim, and Marilyn Noz, and others. I would like to thank Howard Brandt for his suggestion of internal decoherence.
I would like to thank Chris Kalb for suggesting the title.
I would like to thank Jay Wile for some helpful sarcasm.
I would like to thank Stewart Personick for some very constructive discussions.
I would like to thank Matt Riesen for suggesting the use of Rydberg atoms.
I would like to thank Terry the Physicist for useful thoughts on tunneling and for generally hammering the ideas here.
I would like to thank Andy Love for some useful experimental suggestions.
Finally, I would like to thank the six German students at the Cafe Destiny in Olomouc who over a round of excellent Czech beer helped to get the pushed to its final form.
And of course, none of the above are in any way responsible for any errors of commission or omission in this work.