The first decades of the twentieth century were marked by two revolutionary scientific accomplishments, the theory of relativity and quantum mechanics, with repercussions still felt today. Relativity theory and quantum mechanics became the two most important branches of “Modern Physics” that emerged as an alternative to “Classical Physics” (a term often used interchangeably with that of “Newtonian” or “Galilean” physics). No field of science (from astronomy to the life sciences), no field of knowledge (from philosophy to sociology), and no artistic practice (from architecture to the fine arts) was left untouched by these investigations into the nature of our physical universe.