On May 20, 1990, an article titled “‘Iron dumped in ocean may fight global warming” by William Booth of The Washington Post appeared in Sunday papers around the United States. A notion quietly talked about for several years in oceanographic circles was suddenly news. Those quiet oceanographers started yelling at each other and at newspaper editors. Some said alleviating iron-limitation of phytoplankton growth might sink gigatons of carbon from the atmosphere into the deep sea; nonsense, said others. Given the speed at which news appears and again vanishes in the electronic age, the public flap is long over. However, the underlying scientific issues remain important and interesting. Therefore, we have assembled a set of four papers covering the background for the notion that iron availability may set the limit on phytoplankton stocks and growth rates in large regions of the world oceans.