Alexander Grothendieck is 80 today. It’s truly surprising that his strange and marvelous biography — to put it all in one sentence, he rewrote much of the foundation of number theory and geometry in an immense burst of energy in the 1960s, then, over time, came to feel that the mathematical establishment had betrayed him and his ideas, and moved to the Pyrenees to be alone and herd sheep — is not better known.
Read the excellent biographical article by Allyn Jackson, “Comme Appelé du Néant — As If Summoned From the Void”: Part I, Part II. And if that doesn’t sate you, skim through the mass of scanned manuscripts, appreciations both technical and non-, and photographs at The Grothendieck Circle.
My own story: in my last year of grad school I came across Grothendieck’s famous late article, “Esquisse d’un programme” (actually an unsuccessful grant application.) My advisor saw me reading it, and, aware of its seductive effect, told me, “I forbid you from reading the Esquisse until your thesis is finished!”