We shall study the characteristics of a system, its attributes and some basic concepts and strategies for studying them. Our philosophy is that an accounting information system is merely a kind of an information system which in turn is a kind of a system. Therefore, the study of basic principles of systems in general and, information systems in particular, is important for a thorough understanding of accounting information systems. Our approach to the study of accounting information systems, as will become clear, is an engineering one, where one proceeds through a methodical path of specification, design, construction, testing & evaluation, operation and maintenance. A well engineered system is easy to understand, build, maintain, and upgrade.