In 1975, “Tuck Everlasting,” by Natalie Babbitt, hit store shelves. Through the years, the book gained popularity, inspiring children everywhere to fantasize about immortality and dream about what might happen if they ever stumbled upon a magic spring. Today’s children may be able to do more than fantasize about finding a fountain of youth. Dr. Aubrey de Grey leads a team of scientists who are finding ways to radically extend human life. As a biomedical gerontologist – a doctor who studies aging – de Grey isn’t just studying how people age but attempting to slow down the process.