The 50th, 75th, and 125th anniversaries of the International Geophysical Year and the first two International Polar Years (IPYs) will occur in 2007-2008. The first two IPYs and the IGY resulted in major scientific advancements, including measurement of the Antarctic Ice Sheet thickness for the first time, discovery of the Van Allen Belts, and launch of the first U.S. satellite. The International Council for Science (ICSU) and the World Meteorological Organization, among others, have endorsed the concept of another IPY in 2007-2008. The science community currently is discussing how we might organize a new IPY, and the Polar Research Board of the National Academies is leading the U.S. effort by creating a National Committee to IPY. The early consensus appears to be that a new IPY must incorporate a broad, international science effort, include public outreach, and train the next generation of scientists. One of the major themes continually entering discussions is monitoring climate variations and predicting climate changes. This presentation discusses the history of the IPYs and the IGY, outlines current activities of the U.S. and international planning groups for the IPY, and presents the U.S. National Committee vision of the upcoming IPY.