Probes are unmanned spacecraft, and they collect important information for scientists on Earth. They've helped people learn more about asteroids, comets, and other planets such as Mars. Readers learn about the incredible discoveries made by probes in the past, as well as the discoveries present probes are making throughout our solar system. Fact boxes accompany enlightening main text to provide readers with as much information as possible about this fascinating topic. Each page of detailed text is accompanied by vibrant photographs of probes and the amazing places they're sent to explore.