For more than thirty years-half his life-he was obsessively devoted to investigating Everything in the natural world. Nothing escaped his interest-how our eyes see, why the sky is blue, what forces build mountains, how light travels, where water comes from, and-most fascinating of all to Leonardo-the inner workings of the human body. Nothing stopped him. It was illegal to dissect human corpses, so he did autopsies in secret, even devising a clever...

Before Freud, nobody discussed "unconscious" motives, Oedipal complexes, the id and the ego, or freudian slips. Freud was a complicated, often irascible man, sho in 19th-dentury Vienna developed his still-controversial ideas and the new discipline of psychoanalysis.

Albert Einstein: his name has become a synonym for genius. His wild case of bedhead and playful sense of humor made him a media superstar-the first, maybe only, scientist-celebrity. He wasn't much for lab work-in fact he had a tendency to blow up experiments. What he liked to do was think-not in words, but in "thought experiments." What was the result of all his thinking? Nothing less than the overturning of Newtonian physics. Once again, Kathleen...