Albert Einstein (March 14, 1879 – April 18, 1955) was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history. While best known for his mass–energy equivalence formula E = mc2, he received the 1921 Nobel Prize in Physics “for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect”. The latter was pivotal in establishing quantum theory within physics. Einstein’s theories of special and general relativity drastically altered man’s view of the universe, and his work in particle and energy theory helped make possible quantum mechanics and, ultimately, the atomic bomb.