Dragon's Egg is a hard sci-fi that documents an encounter with an alien race that lives on the surface of a neutron star! In all-to-typical hard sci-fi fashion

Dragon's Egg is a hard sci-fi that documents an encounter with an alien race that lives on the surface of a neutron star! In all-to-typical hard sci-fi fashion, you don't really care about any of the characters, but the concepts are truly mind-bending (what looks like a circle to creatures on the surface is an oval to an outside observer due to the extreme magnetic environment; extreme gravity leads to ultra-fast metabolism; etc).