My wife Susan is usually cheerful and upbeat. But this morning I noticed she was teary-eyed and I asked her what was wrong. She replied that ever since her father disclosed that her brother left the island sixty thousand years ago, she hasn’t been able to get her brother off her mind. I put my arm around her and said I can’t imagine what it must be like not knowing what happened to him. I added that I’m intrigued by what Heather the anthropologist said: Lucas made landfall and his genes became part of the human genome. Deadpan says the footprints he discovered won’t make him famous; he’s going to use them as stepping stones.