This text aims to provide a first course in information systems. It features chapter summaries (inputs and outputs of each phase), exercises, examples, issues to debate and a case study of a typical organization. It is intended for first undergraduate and postgraduate courses. This book can be used as a "prequel" to Avisons and Fitzgerald's "Information Systems Development - Methodologies, Techniques and Tools", but also in computer science and business courses where information systems do not go beyond a first course, or a second course is an option.