His The Evolution of Everything: How Selection Shapes Culture, Commerce, and Nature, is a non-fiction exposition of how the mechanisms of evolution which Darwin described have analogies throughout societies.
According to Sumner, Darwin was an egalitarian revolutionary.
He describes Herbert Spencer's corruption of how evolution works -- the caricature encapsulated in the muscularly imperialist phrase "survival of the fittest" -- as the ruling elite's riposte to Darwin's democratic insight:
I can't claim Sumner's little book on evolution entirely worked for me. Some of his contemporary social analogies to Darwinian processes seem a stretch, even if happy ones. Here's an example of one that works -- one I think plausible, though audacious.
I like the idea, but millions of thoughtful people who have staked their thoughts and even their lives on the inability of sclerotic regimes to adapt have been dumbfounded by the flexibility of apparent dinosaurs. But then, sometimes they do disintegrate.
This book is great fun, even if every line of it doesn't entirely hold up. Enjoy.