Grothendieck left IHES in 1970, the second edition was after that. There was a lot of drama in the aftermath, essentially Grothendieck was not happy about how t

Grothendieck left IHES in 1970, the second edition was after that. There was a lot of drama in the aftermath, essentially Grothendieck was not happy about how the more advanced material (SGA 4) he lectured on was kept private to the small group of students that attended the seminar and later reappeared in their publications without much acknowledgement. The eventual SGA 4.5 was a butchered version that only contained enough background to cover Deligne‘s proof.