Les Valiant has won the 2010 Turing Award . (Citation from the ACM website) Over the past 30 years, Leslie Valiant has made fundamental contributions to many aspects of theoretical computer science. His work has opened new frontiers, introduced ingenious new concepts, and presented results of great originality, depth, and beauty. Time and again, Valiant's work has literally defined or transformed the computer science research landscape. Valiant's greatest single contribution may be his 1984 paper "A Theory of the Learnable," which laid the foundations of computational learning theory. He introduced a general framework as well as concrete computational models for studying the learning process, including the famous "probably approximately correct" (PAC) model of machine learning. This has developed into a vibrant research area and has had enormous influence on machine learning, artificial intelligence, and many areas of computing practice,...