These cosmic objects--the leftovers of the formation of our solar system--are the most plentiful bodies in that system. Covered in this fact-filled, up-to-date volume are how asteroids were first discovered, how asteroids and comets formed, their sizes, shapes and orbits, ongoing space flights to these bodies, plans no mine them for their valuable materials, and the very real threat of disaster caused by asteroids and comets impacting the earth.