This book records my efforts over the past four years to capture in
words a description of the form and function of Mathematics, as a
background for the Philosophy of Mathematics. My efforts have been
encouraged by lec- tures that I have given at Heidelberg under the
auspices of the Alexander von Humboldt Stiftung, at the University of
Chicago, and at the University of Minnesota, the latter under the
auspices of the Institute for Mathematics and Its Applications. Jean
Benabou has carefully read the entire manuscript and has offered
incisive comments. George Glauberman, Car- los Kenig, Christopher
Mulvey, R. Narasimhan, and Dieter Puppe have provided similar comments
on chosen chapters. Fred Linton has pointed out places requiring a more
exact choice of wording. Many conversations with George Mackey have
given me important insights on the nature of Mathematics. I have had
similar help from Alfred Aeppli, John Gray, Jay Goldman, Peter
Johnstone, Bill Lawvere, and Roger Lyndon. Over the years, I have
profited from discussions of general issues with my colleagues Felix
Browder and Melvin Rothenberg. Ideas from Tammo Tom Dieck, Albrecht
Dold, Richard Lashof, and Ib Madsen have assisted in my study of
geometry. Jerry Bona and B. L. Foster have helped with my examina- tion
of mechanics. My observations about logic have been subject to con-
structive scrutiny by Gert Miiller, Marian Boykan Pour-El, Ted Slaman,
R. Voreadou, Volker Weispfennig, and Hugh Woodin.