>>11323895Not the best, that is meaningless, but he has a special place among the many excellent mathematicians of the 20th century for having shaped to algebraic geometry as we know it today.
As he said himself, he is more a discoverer of viewpoints and theory-craftsman than anything else, but many of the ideas that he introduced were extremely influential: examples of this are the idea that algebraic geometry should be "relative", ie. thought of as the study of morphisms of varieties X -> Y rather than that of varieties, or the idea that good geometric notions should, in addition to being relative, be compatible with "base change and flat descent".
He tried very hard to make some pretty handwavy geometric ideas more formal and, with the help of others, succeeded to a large extent (eg. parameter spaces, deformation theory, descent theory, intersection theory).
Basically, he not only answered many questions, but he also allowed for many new questions to be asked by introducing a new language and reinterpreting old questions in that framework.
Many developments of the last 50 years, be it in algebraic geometry, homotopy theory, number theory would not have been conceivable, had it not been for his conceptual leaps forward and his incredible dedication.
