Related link: http://www.jmilne.org/math/index.html
A long long time ago, I used to be a mathematician. Occasionally I miss it (mostly the mental discipline.
Being management means never being able to focus on
a single problem to the exclusion of everything else).
James Milne has posted some amazing things here. The real value is, of course, not his research (which I’m not
qualified to judge) but his lecture notes. I can’t imagine a greater public service, or a better use of the internet, than a leading scholar sharing expositions of his subject. Freely, to anyone with the bandwidth to download them.