Few, if any, papers have attracted as much attention as Einsteins June paper on the Special Theory of Relativity and no equation of physics has become part of common discourse except for the equation Einstein presented in his September paper: E = mc2. The concepts of space and time are ubiquitous in physics and, since the Special Theory of Relativity fundamentally altered these concepts, the impact of the June paper on physics has been pervasive. With the additional assertion, made in the June paper, that the speed of light is a constant for all observers, time and space became relative. From his Theory of Relativity, Einstein produced his September surprise: ponderable mass and incorporeal energy are equivalent. Humans distinguish between mass and energy, but Nature does not.