
6 Acknowledgments
My understanding of the work presented in this review was shaped by
a series of annual meetings named after the movie director Frank
Capra. The first of these meetings took place in 1998 and was held
at Capra’s ranch in Southern California; the ranch now belongs to
Caltech, Capra’s alma mater. Subsequent meetings were held in
Dublin, Pasadena, Potsdam, State College PA, and Kyoto. At these
meetings and elsewhere I have enjoyed many instructive
conversations with Warren Anderson, Patrick Brady, Claude Barrabès,
Leor Barack, Lior Burko, Manuella Campanelli, Steve Detweiler,
Eanna Flanagan, Scott Hughes, Werner Israel, Carlos Lousto, Yasushi
Mino, Hiroyuki Nakano, Amos Ori, Misao Sasaki, Takahiro Tanaka,
Bill Unruh, Bob Wald, Alan Wiseman, and Bernard Whiting. This work
was supported by the Natural Sciences and Engineering Research
Council of Canada.
