Winston Churchill, whose output as a writer was so prodigious that one might reasonably wonder whether he was paid by the page, was him self put off by long works. As prime minister of Great Britain, he once pushed away a report from a junior minister, observing, "This paper, by its very length, defends itself against the risk of being read." No doubt some laymen will glance at the study that follows and be deterred from further consideration by the fact that the study is a scien tific one. If that is a hurdle for you, I hope you will join me in getting over it, because, if you do, you will find that the authors have quite a story to tell. That story is about change-the possibility that the climatic patterns of the world are in a transition to warmer weather that could lead to a rise in the sea level. You may not have thought much about the sea level previously; it was something we took for granted. But since we have taken it as a given for so long, the adjustments we may have to make will be profound. When you stop to think about all the areas of our lives that could be affected by climatic change, you will be amazed: we have planned our cities, developed our manufacturing techniques, and chosen our en vironmental protection strategies on the assumption of a stable seaJevel.