The history of humanity is the history of a silent war against oblivion. From a clay tablet buried in the foundation of a temple by a Sumerian king in 2000 B.C. to the Voyager Golden Records launched into the depths of space in 1977, we have always acted with the same primal urge: "I was here, I lived, and my words shall not vanish." However, history has taught us a painful truth: Everything physical eventually decays. Paper yellows, maps get lost, and centralized authorities collapse. Today,...