In March 1998, the Isaac Newton Institute for Mathematical Sciences was privileged to receive a visit from Deputy Prime Minister Tony Tan, who
invited the Institute to collaborate with the National University of Singapore in organising a millennial conference on Mathematics and Theoretical Physics. I was happy to be involved in this exciting venture, which came to fruition exactly two years later. This volume, containing a wide range of papers presented at the Conference, reflects both the international, indeed global, nature of research in the subject, and the symbiotic manner in which mathematics can interact with theoretical physics to the mutual benefit of both.