Simply put, a mathematician is someone who studies math, just like a scientist studies science, a zoologist studies animals, or a magician studies magic (not that they exist). There have been many great mathematicians over the years, many of whom made great discoveries, such as number theory (which is important for computers) or the Pythagorean Theorem. They do not actually do calculations, though, so much as seek to prove different conjectures and ideas, and search for patterns.
Below, we have the profiles of many different mathematicians, some alive, many deceased. In each you’ll find a short biography, and some information on what they contributed to the field of mathematics.