The rich geological record of the Cretaceous Period reveals a world that experienced extreme climatic warmth and significantly higher global sea levels than today. It therefore provides a natural case study of the Earth in ‘greenhouse’ climatic mode, which this interdisciplinary textbook analyses from the perspective of Earth System Science. After surveying the evidence for conditions on the Cretaceous Earth, this book explores the interactions between the physical, chemical and biological processes, within the Earth and at its surface. These processes control the prevailing environmental conditions on Earth and the book highlights the major differences between the Cretaceous and the present world. Finally, the mass extinction that terminated the period, and its possible causes, are investigated. Designed for undergraduate and graduate courses, this textbook features chapter summaries, focus boxes, and questions and answers throughout the text. The book is supported by a website hosting sample pages, selected illustrations, and worked exercises.