Richard S. Westfall  is best known for his biography of a mathematician who was a key figure in what?
Richard S. Westfall:  He is best known for his biography of Isaac Newton and his work on the scientific revolution of the 17th century. Isaac Newton: Sir Isaac Newton {'1': ", '2': ", '3': ", '4': "} ( ; 25 December 1642 – 20 March 1726/27) was an English mathematician, astronomer, and physicist (described in his own day as a "natural philosopher") who is widely recognised as one of the most influential scientists of all time and a key figure in the scientific revolution.
i don't know