On May 27, 1931, Auguste Piccard became the first human to enter the stratosphere, flying an experimental balloon he invented himself. Thirty years later, his son Jacques went to the bottom of the earth, descending to the Mariana Trench in a submarine built by him and Auguste. To this day, no one has gone deeper. Bertrand, the third generation, was the first person to fly around the world non-stop in a balloon. Now, he&#8217;s building his own craft: a solar-powered plane to circumnavigate the globe.<BR> <BR>In <I >The Explorer Gene</I>, Tom Cheshire asks how three generations of one family achieved such extraordinary feats, often with the consensus against them. None of the Piccards set out to explore: Auguste was a physicist, Jacques an economist and Bertrand a psychiatrist. Was it fate, a famous family name &#8211; or their explorer gene?