Book which you must read.
I've just finished Last and First Men by Olaf Stapleton. You have to read this-- it's a complete headfuck, a revelation. This guy was a visionary. I can't belive he was writing in the 30's.
The book is incredible. It's an attempt to conceptualise the whole future of humanity, civilizations rising and falling, disintegrating and coalescing... it's incredible. There's a terrific sense of a mind trying to reconcile the very worst of human nature with the very best-- and from time to time, actually succeeding.