The fifth published book in the "Chronicles of Narnia," although chronologically the third. This one focuses, unsurprisingly, on a horse and a boy. I was deeply disappointed to find that Lewis had no interest, despite the title, of making a talking horse more important than a human: the horse Bree features heavily in the book, but it's really mostly about the boy Shasta. Lewis has written a land of talking animals, but remains a very humans-first kind of guy ...
Shasta is a young boy in the country of Calormene. Everyone there addresses each other "O my father," "O my son" or similar. Very early on, Shasta overhears the man he thought was his father (who he doesn't like much) bartering to sell him. The potential buyer says "This boy is manifestly no son of yours, for your cheek is as dark as mine but the boy is fair and white like the accursed but beautiful barbarians who inhabit the remote North." As the Calormenes turn out to be a relatively treacherous race and our hero isn't one of them, it certainly seems like Lewis favours the white humans over the dark humans.
Shasta meets the talking horse Bree (in Calormene horses don't talk, but Bree is a captured Narnian horse - who has told no one other than Shasta that he can talk), and together the two flee their servitude. They have many adventures on the way to Narnia. Lewis's manifestation of God, Aslan the Lion, inevitably plays a part.
I got a big laugh out of what Shasta said at the end of the book: he was pleased with his new situation "even though Education and all sorts of horrible things are going to happen to me."
As with the other Narnia books I've (re-)read recently (I'd never read this one, but had read several of the others as a child), this one manifests a number of things that are considered a problem in 2019: casual racism and "White Saviour" being the more obvious ones. His sexism isn't quite as on display this time. But, like the others, if you can get past those things, it's still a fun story.