Dragons Egg by Robert Forward had always been one of my favorites. Asks the question "what would like be like if it evolved on a neutron star," and has 20 pages of his notes on working out the physics at the end of the book.
I read Dragon's Egg and the sequel, Starquake, as a teenager. I remembered them being deeply engrossing.
I revisited the first one 20-ish years later in an attempt to get my partner interested. I only made it a few chapters before I decided to abandon the attempt. There are some really good parts (the science stuff), but the way the human characters' interactions were described I just could not get past.
