This book provides the reader with an overview of the nature of the Arctic climate system and its links with the global system. The book begins with a historical perspective, addressing the early exploration of the Arctic, the growth of systematic observations and the advent of the modern research era. This is followed by discussion of the basic physical and climatic characteristics of the Arctic, laying groundwork for subsequent chapters. These address the atmospheric heat budget, the atmospheric circulation, the surface energy budget, the hydrologic budget, atmosphere–ocean–sea ice interactions and regional climate regimes. Modeling is an important tool in Arctic climate research, and is accorded its own chapter. Following a review of past climates (paleoclimates), the book closes with an assessment of recent climate variability, trends and the projected future state of the Arctic. While the subject matter is targeted at the level of the advanced undergraduate and graduate student, it should be accessible to anyone with an interest in the Arctic and a basic understanding of climate science. The text contains numerous illustrations to help the reader, and references to many review papers on specialized topics.