A selection of
Grothendieck's unpublished mathematical writings
Correspondence  A selection of letters from Grothendieck to
various people
Some of Grothendieck's published
mathematics
Notes of courses given by Grothendieck

Introduction au langage fonctoriel.
Original typed notes, taken by M. Karoubi, of a course
taught by Grothendieck in Algiers in November 1965. 77 pages.

Groupes de BarsottiTate et Cristaux de Dieudonné.
Notes by M. Hakim and J.P. Delale of a lecture course given by
Grothendieck at U. of Montreal in the summer of 1970. 150 pages.

Introduction to Functorial Algebraic Geometry.
Notes written by Federico Gaeta at (the first part of) a 100hour course given by Grothendieck in Buffalo, NY in the summer of 1973. These are not based on prenotes by Grothendieck and to some extent represent Gaeta's personal understanding of what was taught there. 168 pages.
Surveys and overviews of Grothendieck's work