Oooh, thank you! I did get him Equal Rites, which is a discworld novel; I thought about which part of the series might interest him because once you read one, you're generally hooked.

I also got him Passage by Connie Willis (that was my wife's suggestion), so I'm happy to see another recommendation from her on here.

Also I ADORE Diane Duane and am upset at myself for not thinking to include something by her, so thanks for the reminder!

I have heard much about the Muderbot series but not read it, so that's a good reminder for me, too!

Thanks so much!