Dragon's Egg

Dragon's Egg is a cross between Mission of Gravity by Hal Clement and Microcosmic God by Theodore Sturgeon. In my opinion it rates right up there with them both.

The story is about the discovery of a neutron star close enough to visit. While the team sent to study the neutron star are busy learning all they can about this mysterious visitor, unbeknownst to everyone there is a native civilization of creatures developed to live on the neutron star. These nearly microscopic creature live at an incredibly advanced rate of life. An hour of our time is the equivalent to a hundred years to them.

Dragon's Egg is a fascinating tale of scientific discovery and adventure. I highly recommend this.