What exactly is artificial intelligence? This book is for all those who are curious to learn what artificial intelligence (AI) is. It is a purposely brief introduction to the subject, that has been kept as elementary as possible to make it user-friendly. It has been written by reputed researchers in the field, on the initiative of the GDR IA, a research group of the French National Center for Scientific Research (CNRS), dedicated to the formal and algorithmic aspects of AI. What exactly is artificial intelligence? This book is for all those who are curious to learn what artificial intelligence (AI) is. It is a purposely brief introduction to the subject, that has been kept as elementary as possible to make it user-friendly. It has been written by reputed researchers in the field, on the initiative of the GDR IA, a research group of the French National Center for Scientific Research (CNRS), dedicated to the formal and algorithmic aspects of AI. This makes it unique in its kind because it aims at covering artificial intelligence in all its aspects and all its diversity. It comprises a brief history of AI and a presentation of its key concepts; it describes the principal areas where AI is at work, the interactions between AI and other scientific disciplines and finally answers questions that are often raised about AI. It ends with a glossary of technical terms used and a selected list of references. This book has been translated into English by Rosemary Patricot and Philippe Dague This makes it unique in its kind because it aims at covering artificial intelligence in all its aspects and all its diversity.