The US National Parks have been called 'America's Best Idea'. They also provide a beautiful and accessible set of examples around which to structure an introductory geology course, motivating students' curiosity about the science that explains the dramatic landscapes of our nation's unique protected lands. This book introduces core geologic concepts such as volcanism, mountain building, deep time, tectonics, sedimentation and glaciation using our beloved Parks as touchstones. Each chapter builds a broader narrative of how the country's geologic foundations were constructed through time, demonstrating the broader connections between national parks rather than viewing them as isolated entities.