Dragon's Egg is a fascinating story by Robert L. Forward about life that has arisen on a neutron star, and explores the hurdles such beings would face. A neutron star is passing near our solar system and scientists take the opportunity to study it. Meanwhile, life is evolving at an incredibly rapid rate on its surface. In a world dominated by unimaginable gravity, intense magnetic fields and literally white hot temperatures, nuclear life arises. I loved this book for its depiction of life evolving in otherworldly conditions while still feeling plausible. Dragon's Egg explores how a species could arise and become a civilization and eventually make contact with aliens (the aliens being the Earth scientists orbiting the star). It's unlike any book I've ever read, and I look forward to getting ahold of the sequel, "Starquake".
On a neutron star, the cheela, a form of intelligent life whose hour equals more than one hundred human years, struggle to progress from the beginnings of agriculture to the discovery of science. Reprint.