This book gives a condensed introduction to information systems and their use in companies and organisations. Their role in organisations and how they can contribute to a successful enterprise is explained. The book has a non-technical focus, but introduces fundamental technical concepts and vocabulary, such as computer parts, data storage, databases and networks. The fundamentals of systems development are explained. Essentials of Information Systems introduces the concept of information systems in a condensed and accessible form. The book equips the reader with basic knowledge of the information systems necessary in any modern organisation. This book can be read by anyone interested in information systems. It is particularly suitable for introductory courses in business and information systems.