Clifford Stoll could talk about the atmosphere of Jupiter. Or hunting KGB hackers. Or Klein bottles, computers in classrooms, the future. But he's not going to. Which is fine, because it would be criminal to confine a man with interests as multifarious as Stoll's to give a talk on any one topic.

Instead, he simply captivates his audience with a wildly energetic sprinkling of anecdotes, observations, asides -- and even a science experiment. After all, by his own definition, he's a scientist: "Once I do something, I want to do something else."