Geology is a little like having the world’s biggest and best time machine at one’s disposal. The field of enquiry is the whole Earth, its 4.54-billion-year history, and everything that has formed on our planet over that time. ‘What is geology?’ explains that the geological record is a record of ancient worlds, of dynamic and evolving landscapes and submarine-scapes. Geology is a science encompassing virtually all the other sciences—chemistry, physics, biology, geography, oceanography, and many others—and involves or impinges upon many of the humanities and arts, and day-to-day life. It involves looking deep into the Earth’s structure, but also extends to the observation of other planets and moons.