Fokko du Cloux
Fokko du Cloux was one of the founding members of the atlas project. He was instrumental in converting representation theory of Lie groups into an algorithm suitable to be put on a computer. He also wrote the atlas software to do just that. This is the the software that was used by David Vogan and Marc van Leeuwen to compute Kazhdan-Lusztig-Polynomials for E8.
In November of 2005 Fokko was diagnosed with ALS. He was actively engaged in the atlas project until he died on November 10, 2006.