en years ago, a school lesson on drought in sub-Saharan Africa might have required students to read a textbook and, perhaps, to watch a film. Today, with the help of computers and the Internet, that lesson could be transformed from a one-way flow of information into an interactive process. Students could go on-line to search for the latest thinking on the causes of drought. They could use e-mail to interview African-studies specialists on the cultural impact of the problem. And they could apply digital geography and weather tools to simulate the effects of drought on local crops and the environment.