Information System is an important area of study in modern management. In this book, the fundamentals of information system, meaning and role of management information system, management organisational theory and system approach is covered. Various policies and techniques related to information system are also appended in this book to make it more comprehensive in all manners. In Unit 1, the introduction part of Information system is covered. In Unit 2, Systems implementation and significance of computer Based information system is covered. In Unit 3, Systems Acquisition, Implementation, Security and maintenance is enclosed to make the text more Comprehensive. In Unit 4, Emphasis has been laid down on Decision Support System and Key Issues of MIS Management.