He seems to have been quite a productive sort of man and appears to generally have been content to stick to his own artistic concerns with almost no reference to developments in the greater art world.
I'm feeling a bit lazy this morning so rather than try and sum his work up here's an excerpt from "Symbolism" , by Michael Gibson.
"It was only in the 1890s that he began to use the luminous, musical tones of pastel and oils. These became the dominant media of the last fifteen years of his life. Redon's art was always commanded by his dreams, but the thematic content of his work over his last twenty years is more densely mythical, brimming with new-found hope and light which rose quite unexpectedly out of the depths of the artist's personality. This is particularly apparent in the various canvasses depicting the chariot of Apollo, the god of the sun."
I've also been drawn to many of the ideas he writes about in his diaries to himself. This one is a current favourite.
"Materials have their own secrets to reveal, they have their own genius. It is through them that the oracle speaks"