A social democrat friend who knows basically nothing about socialism and was a berniecrat is looking for book recommendations, what is a good book to recommend to him?

I sort of dived in the deep end when I first started (perhaps unproductively ) and I they're the type of person who would probably benefit a lot from nice prose and nothing SUPER heavy, but I also know a lot of intro books are full of BS that needs to be deprogrammed later(especially stuff that includes left-anticommunism) so I'm being cautious.

What would you recommend?