This chapter introduces the field of artificial intelligence (AI) through a review of its core themes, history, major research areas, and current trends. It gives a brief history of AI with an account of some of its relatively recent major accomplishments. These include knowledge-based expert systems, chess players, theorem provers, natural language processing, and a new killer application. There are almost a dozen distinct subfields of AI research, each with its own specialized journals, conferences, workshops, and so on. The chapter provides a concise account of the research interests in each of these subfields. Flourishing recent trends include soft computing, AI for data mining, agent-based AI, cognitive computing (including developmental robotics and artificial general intelligence), and the application of AI in cognitive science. Research into artificial intelligence is thriving as never before, and promises continuing contributions, both practical to engineering and theoretical to science.