We are on the cusp of a new great era of exploration, of the most important planet we know. This book introduces and formalizes the topic of using increasingly capable robotic explorers for our home planet. We have long used robotic spacecraft to explore space, the moon, the other planets of our solar system, and their moons. At least one of our spacecraft, Voyager, has left the solar system, and is still returning data on interstellar space. Unmanned explorers precede human ventures into space, and have been to many more distant locations than we have. We can use long operational time platforms such as aerostats, flying drones, underwater drones and such for exploration of the remote reaches of our home. Even now, drones are being deployed into hurricanes. Multiple cooperating systems, non-homogeneous, are enabled by advances in communication, computation, and smart sensors. Software advances in clustering and swarm behavior enable the deployment of autonomous systems. It is an exciting time. Our own planet has been extensively but not exhaustively explored by humans, from the depths of the sea to the highest layers of the atmosphere, and to the "four corners" of the Earth. Now, with the emergence and maturation of advanced robotic technology and "big data" techniques, we can do more. It is increasingly valuable to collect, store, and manage massive databases of information on our own planet. These data can be used to develop and refine models of our environment and ecosystem, which may be critical to our survival.