Eugene Paul "E. P." Wigner was a Hungarian American theoretical physicist and mathematician and a joint winner of the Nobel Prize for his contribution to nuclear physics. From the beginning of his career, Wigner had made many significant cross-disciplinary discoveries. He established the importance of symmetry principles in quantum mechanics and was one of the first scientists to apply quantum mechanics to the theory of solids and chemical kinetics. He also led the endeavour to design the first high-powered reactors to be used in World War II. He was responsible for the full development of the R-matrix theory for nuclear reactions. More than forty doctoral students studied theoretical physics under his supervision at the Princeton University. As a statesman, he lobbied for civil defense. Later in life, he became inclined towards the philosophy of science. Wigner held memberships in different associations like the American Philosophical Society, the American Mathematical Society, the American Association of Physics Teachers, the Royal Netherlands Academy of Sciences and Letters, and the Austrian Academy of Sciences. He was also a corresponding member of the Gesellschaft der Wissenschaften, Gottingen, and foreign member of the Royal Society of Great Britain. In his final years, he remained active in fostering cultural and scientific ties between Hungarians and the world.