The study text is aimed at explaining the basic concepts in the field of Information Systems. The first chapter of this discipline deals with a theoretical introduction to the subject and the definition of the basic concepts of information systems theory. The second chapter then introduces the reader to the issue of knowledge-based systems and their design. The third chapter introduces the issues of information and knowledge systems architecture. The fourth chapter discusses the different types of information and business information systems. The last fifth chapter deals with the issue of School Information Systems and is the culmination of the whole text.