Within our solar system are four rocky planets. We have named them the inner planets because they are closest to the sun. But what do we know about these rocky places? The Inner Planets explores Earth and its nearest neighbors and uncovers the space science and space missions that have helped us learn about these rocky worlds. Science-filled explanatory text reveals what and how we have learned about the inner planets, the history of this space science, and what the future holds. Detailed sidebars set out fascinating facts about the rocky planets. Use your STEM and critical-thinking skills to complete the "Your Mission" activities to find out how you would solve space problems and head missions to discover more about our solar system's inner worlds. Budding space scientists are encouraged to think about what your contribution to space science could be and if a future career in this field might be for you. The Inner Planets completes the mission to explore our home planet and its neighbors!