I was at my best at a little past forty, when I was a professor at Oxford.
Beauty is the first test: there is no permanent place in the world for ugly mathematics.
I wrote a great deal... but very little of any importance; there are not more than four of five papers which I can still remember with some satisfaction.
A mathematician, like a painter or a poet, is a maker of patterns. If his patterns are more permanent than theirs, it is because they are made with ideas.