DIVThe definitive account of the Everests of mathematics–the seven unsolved problems that define the state of the art in contemporary math/DivDIVIn 2000, the Clay Foundation announced a historic competition: whoever could solve any of seven extraordinarily difficult mathematical problems, and have the solution acknowledged as correct by the experts, would receive $1 million in prize money. There was some precedent for doing this: In 1900 the mathematician David Hilbert proposed twenty-three problems that set much of the agenda for mathematics in the twentieth century. The Millennium Problems–chosen by a committee of the leading mathematicians in the world–are likely to acquire similar stature, and their solution (or lack of it) is likely to play a strong role in determining the course of mathematics in the twenty-first century. Keith Devlin, renowned expositor of mathematics and one of the authors of the Clay Institute’s official description of the problems, here provides the definitive account for the mathematically interested reader./DivDIVBKeith Devlin/Bis the Dean of the School of Social Science at St. Mary’s College, Moraga, California, and a Senior Researcher at the Center for the Study of Language and Information at Stanford University. He is the author of 22 books, one interactive CD-ROM, and over 65 technical research papers in mathematics. His voice is heard regularly on National Public Radio, on such programs as Weekend Edition, Talk of the Nation, Science Friday, Sounds Like Science, and To the Best of Our Knowledge. His previous books include Life by the Numbers, the companion to a PBS series that aired in April and May, 1998; Goodbye Descartes: The End of Logic; and The Language of Mathematics: Making the Invisible Visible./Div