Bourbaki, right. I remember trying to read their "Set Theory" book. A page dedicated to proving that x = x, etc. Probably written for the people who already know stuff, not for students. Well, there's another such book, Bahrendregt. When I read it, I know that 99.99% of readers are totally clueless, because hardly anybody is familiar with e.g. Grothendieck toposes, half-implicitly used there.