When observing the recent past of mathematical history, you encounter the name Nicolas Bourbaki quite often. The reason for this is quite simple, actually. Nicolas Bourbaki, born 1935, might be the author of the most math books in history. More importantly, he has written books ranging from mathematical history to algebraic topology, and even calculus. Where it becomes mysterious, however, is that not a single person has seen him. That is because no one by the name of Nicolas Bourbaki has ever lived.
In 1914, a state of emergency was declared in France and nearly everyone was drafted into the military. The consequent blow to the education system of high schools and universities was massive. Students in France were not getting the education they needed and therefore mathematicians were not being raised. Despite this, however, renowned mathematicians like Fermat and Poincare were raised.
In Germany, the opposite was true. Even though the war raged on, brilliant mathematicians like David Hilbert, Helmut Hasse, Emmy Noether, Wolfgang Krull, Emil Artin, and Bartel Leendert Van der Waerden were brought up and learned the fundamental study of math, Algebra.
A group of patriotic mathematicians, who at the time studied at École normale supérieure, decided that France had fallen too far behind Germany and set out to solve the problem through a series of seminars. In time, they started to think more universally and came to the conclusion that Mathematics as a whole must be rewritten. For example, they did not like the Calculus book they were reading, so they decided to rewrite it.
The best way to express their thoughts on modern mathematics was through writing books. However, they decided that it would be best to write as one author, rather than write their individual books. Their most fundamental book, which they frequently revised, Elements de Mathematiques, would leave a massive imprint on contemporary mathematics.
So there it is; the start of Nicolas Bourbaki’s legend, a secret organization. At first, it was only Henri Cartan, Claude Chevalley, Jean Delsarte, Jean Dieudonne, and Andre Weil.