Dualities in integrable systems and N=2 SUSY theories

We discuss dualities in the integrable dynamics behind the exact solution t o the N = 2 SUSY Yang-Mills theory. It is shown that T duality in the strin g theory is related to the separation of variables procedure in the dynamic al system. We argue that there are analogues of S duality as well as three- dimensional mirror symmetry in the many-body systems of Hitchin type govern ing the low-energy effective actions.