In Thunderstones and Shooting Stars, Robert T. Dodd gives us an up-to-date report on these questions. He summarizes the evidence that leads scientists to believe that most meteorites come from asteroids, although a few come from the moon and a few more from a planet, probably Mars. He explains how chondrites--the most numerous and primitive of meteorites--contribute to our evolving picture of the early solar system, and how some of them may tell us of events that took place beyond the sun and before its birth. Finally, he examines the controversial hypothesis that impacts by asteroids or comets have interrupted the evolution of life on Earth, accounting for such geological puzzles as the rapid demise of the dinosaurs.