John von Neumann (/vɒn ˈnɔɪmən/; December 28, 1903 – February 8, 1957) was a Hungarian-American mathematician, physicist, computer scientist and engineer. Von Neumann was regarded as perhaps the mathematician with the widest coverage of the subject in his time and was said to have been “the last representative of the great mathematicians who were equally at home in pure and applied mathematics”. He integrated pure and applied sciences.
Von Neumann made major contributions to many fields, including mathematics (foundations of mathematics, functional analysis, ergodic theory, group theory, representation theory, operator algebras, geometry, topology, and numerical analysis), physics (quantum mechanics, hydrodynamics, and quantum statistical mechanics), economics (game theory), computing (Von Neumann architecture, linear programming, self-replicating machines, stochastic computing), and statistics. He was a pioneer of the application of operator theory to quantum mechanics in the development of functional analysis, and a key figure in the development of game theory and the concepts of cellular automata, the universal constructor and the digital computer.
Von Neumann published over 150 papers in his life: about 60 in pure mathematics, 60 in applied mathematics, 20 in physics, and the remainder on special mathematical subjects or non-mathematical ones. His last work, an unfinished manuscript written while he was in the hospital, was later published in book form as The Computer and the Brain.