I opened my favourite online news website last week, to find out a link to a piece of news titled about a mathematician called Alexander Grothendieck passing away. At first - I feel ashamed - I thought "who is this guy?", then I made a quick search on Google to find out that he was quite a character, not to mention a Fields medalist (wooops).
On his Wikipedia page we find some interesting facts on his bio, such as the fact he have been stateless most of his life, he left a prestigious academic position over a dispute on military fundings and he retired at the age of 60 and live in complete isolation until his death.
As a mathematician, Grothendieck published important works in functional analysis and at the time of his Ph.D. studies he was supervised by no less than Schwartz,but his major contributions belong to algebraic geometry. His most famous paper is the seminal work Sur quelques points d'algèbre homologique (1957), of which you can find a "simplified" and English version here. According to reviews, in such work Grothendieck managed to rise homological theory to a superior level of abstraction - if this is even possible.
A pacifist and a social activist, extremely focused on ethics and the serving purpose of science and research, not to mention a math lover. If you, as myself, got curious from these fragments of his life and powerful personality, I invite you to read this very well-written biography: