John J. Tyson is a systems biologist and mathematical biologist who serves as NIMML Institute member, and is the former president of the Society for Mathematical Biology. He is known for his research on biochemical switches in the cell cycle, dynamics of biological networks and on excitable media. Since receiving his PhD in chemical physics at the University of Chicago in 1973, John Tyson has been studying temporal and spatial organization in chemical, biochemical and biological systems. He has focused on the macro-molecular reaction networks that process information in living cells and initiate appropriate responses in terms of cell growth, division and death. He represents the dynamics of these reaction networks in terms of mathematical equations, using computer simulations to work out the precise behavior to be expected of the network. By comparing simulations with experimental data, the computer models can be tested, refined and developed, eventually, into tools for accurate predictions of the physiological responses of healthy and diseased cells. He has been involved in some seminal studies related to computational immunology.