Three Fields Medallists gave lectures at ICTP's School and Workshop on Dynamical Systems held from 30 July to 17 August. John Willard Milnor, Princeton University, who spoke about the increasingly important role played by mathematics in genetics, won the Fields Medal in 1962 for his proof that a seven-dimensional sphere can have several different structures. Gregori Aleksandrovic Margulis, Yale University, who spoke about geometry of numbers and inequalities for integral operators, received the Fields Medal in 1978 for his pathbreaking insights on subgroups of Lie groups. Jean-Christophe Yoccoz, College de France, who spoke about "Quasi-Periodic Dynamics for p-adic Rational Maps," was given the Fields Medal in 1994 for his unique contributions to our understanding of dynamical systems. The Fields Medal, which began in 1936, is considered the world's highest honour in mathematics.