Hey,
Fourier's concept has very little to do with calculus. What is awesome is that any function can be "parametrized" by some basis consisting of Cosines and Sines. This allows us to deal with much bigger set of functions. Also, some impossible mathematical processes in normal space can be possible in Fourier space.
I guess Fourier's important to me 'cause his works' important to my work which is closely related to signals and a lot of math to go with it. (Correction: Ugly math!)
I think I am very subjective about Newton. He was a great scientist but a bad aristocrat. He used his science to somewhat questionable means to give himself political power. He became more of a politician than a scientist. And, you know how we, Japanese people, respect politicians. ...
Einstein is also a great scientist. The theory of relativity was only tiniest one of his work. His greatest work is about the properties of light. Light is particle yet wave, wave yet particle. Light is neither particle nor wave. Brah Brah Brah ... Yari Yari Yari ... You can read about them.
Random walker,
Tomo