Richard Gott is Professor of Astrophysics at Princeton University. A Phi Beta Kappa, summa cum laude graduate in Physics from Harvard in 1969, he received his Ph.D. in Astrophysics from Princeton in 1973. He was a postdoctoral fellow at the California Institute of Technology and at Cambridge University before returning to join the Princeton faculty. He is the author of the Time Travel in Einstein's Universe (Phoenix). He has written on time travel and other subjects for Time, Scientific American, New Scientist and Nature. He is one of the world's experts on parallel universes, string theories and cosmic origin. Robert Vanderbei is Professor and Chair of the Department of Operations Research and Financial Engineering at Princeton University. A summa cum laude graduate in Chemistry from Rensselaer Polytechnic Institute in 1976, he received his Ph.D. in Applied Mathematics from Cornell University in 1981. As an amateur astronomer, Vanderbei has taken, from his backyard, astonishing and very highquality photographs of astronomical objects: these photos rival the best of those taken from some of our greatest observatories.