Michael James David Powell FRS was “a British numerical analyst who was among the pioneers of computational mathematics” [1]. He was the inventor/early contributor of Quasi-Newton method, Trust-Region method, Augmented Lagrangian method, and SQP method [1,2]. Each of them is a pillar of modern numerical optimization. He also made significant contributions to approximation theory and methods [1,2,3].
Among numerous honors, Powell was one of the first two recipients of the Dantzig Prize [4] from the Mathematical Programming Society/Society for Industrial and Applied Mathematics (SIAM). This is considered the highest award in optimization.
See also his Google Scholar profile [5] and the memorial page at [6].
[1] https://royalsocietypublishing.org/doi/full/10.1098/rsbm.201...
[2] https://en.wikipedia.org/wiki/Michael_J._D._Powell
[3] https://www.cambridge.org/highereducation/books/approximatio...
[4] https://en.wikipedia.org/wiki/Dantzig_Prize
[5] https://scholar.google.com/citations?user=p3kDmy0AAAAJ&hl