The International Polar Year (IPY) 2007–2008 will be the largest and most interdisciplinary polar science project ever. David Carlson, director of the IPY International Programme Office (IPO), reports that some 50,000 investigators from more than 60 countries organized in more than 200 international clusters of projects will endeavor to study nearly every aspect of the poles. The projects cover a broad range of physical, life, and social sciences. The data from these projects will be unprecedented in their breadth and diversity and will be the primary legacy of IPY.