This volume provides a snapshot of topics engaging theoretical physicists at the end of the twentieth century and the beginning of the twenty-first. Based on seven of the courses given at the 1999 CRM Summer School in Banff, the chapters provide timely, diverse and exciting views of their fields. The contributions include: - Supersymmetric Yang-Mills theory and integrable systems (E. D'Hoker and D.H. Phong) - Branes, black holes and anti-De Sitter space (M.J. Duff) - Turbulence (K. Gawedzki) - Bose--Einstein condensation and coherent matter waves (A. Griffin) - Deformed Virasoro and elliptic algebras (S. Odake) - Mesoscopic physics (B. Simons, A. Atland) - QCD in extreme conditions (F. Wilczek) Young physicists will find in these chapters pedagogical introductions to subjects currently active in theoretical physics, and more seasoned physicists will find a chance to share the excitement of fields outside their immediate research interests.