Table of contents: Plenary Lectures * V.I. Arnold: The Vassiliev Theory of Discriminants and Knots * L. Babai: Transparent Proofs and Limits to Approximation * C. De Concini: Poisson Algebraic Groups and Representations of Quantum Groups at Roots of 1 * S.K. Donaldson: Gauge Theory and Four-Manifold Topology * W. Muller: Spectral Theory and Geometry * D. Mumford: Pattern Theory: A Unifying Perspective * A.-S. Sznitman: Brownian Motion and Obstacles * M. Vergne: Geometric Quantization and Equivariant Cohomology * Parallel Lectures * Z. Adamowicz: The Power of Exponentiation in Arithmetic * A. Bjorner: Subspace Arrangements * B. Bojanov: Optimal Recovery of Functions and Integrals * J.-M. Bony: Existence globale et diffusion pour les modeles discrets * R.E. Borcherds: Sporadic Groups and String Theory * J. Bourgain: A Harmonic Analysis Approach to Problems in Nonlinear Partial Differatial Equations * F. Catanese: (Some) Old and New Results on Algebraic Surfaces * Ch. Deninger: Evidence for a Cohomological Approach to Analytic Number Theory * S. Dostoglou and D.A. Salamon: Cauchy-Riemann Operators, Self-Duality, and the Spectral Flow