Three Roads To Quantum Gravity

viii THREE ROADS TO QUANTUM GRAVITY
Jurgen Renn, Kelle Stelle, Andrew Strominger, Thomas
Thiemann and Edward Witten. I add a special word of
appreciation for the founders of the ®eld of quantum gravity,
including Peter Bergmann, Bryce DeWitt, David Finkelstein,
Charles Misner, Roger Penrose and John Archibald Wheeler.
If they see many of their ideas here, it is because these are the
ideas that continue to shape how we see our problem. Our
work has been supported generously by the National Science
Foundation, for which I especially have to thank Richard
Issacson. In the last several years generous and unexpected
gifts from the Jesse Phillips Foundation have made it possible
to concentrate on doing science at a time when nothing was
more important than the time and freedom to think and work.
I am grateful also to Pennsylvania State University, and
especially to my chair, Jayanth Banavar, for the supportive
and stimulating home it has given me over the last six years,
as well as for showing some understanding of the con¯icting
demands placed upon me when I found myself with three
full-time jobs, as a scientist, teacher and author. The theory
group at Imperial College provided a most stimulating and
friendly home from home during the year's sabbatical during
which this book was written.
This book would not exist were it not for the kind
encouragement of John Brockman and Katinka Matson, and I
am also very grateful to Peter Tallack of Weidenfeld &
Nicolson, both for his encouragement and ideas and for being
such a good editor, in the old-fashioned sense. Much of the
clarity of the text is also due to the artistry and intelligence of
John Woodruff's copy editing. Brian Eno and Michael Smolin
read a draft and made invaluable suggestions for the organization
of the book, which have greatly improved it. The support
of friends has continued to be essential to keeping my own
spirit alive, especially Saint Clair Cemin, Jaron Lanier and
Donna Moylan. Finally, as always, my greatest debt is to my
parents and family, not only for the gift of life but for imparting
in me the desire to look beyond what is taught in school, to try
to see the world as it may actually be.
Lee Smolin
London, July 2000