John von Neumann was a Hungarian-American mathematician, physicist, computer scientist, and polymath who made major contributions to a variety of fields. He is widely regarded as one of the most influential mathematicians of the 20th century and is credited with being one of the founders of modern computer science. He is also known for his work in game theory, economics, and quantum mechanics. Von Neumann's most famous contribution to mathematics was his development of the concept of a 'von Neumann algebra, ' which is now an important tool in abstract algebra.