Virtual presence of Internet and availability of infor-mation on the net have led to information systems becoming an inseparable part of organizations. Today, computer-based information systems are extensively used for acquisition, storage, and dissemination of data throughout the organizations. These information systems, however, need to be backed by sound software development activities. The systems analysts play a key role in development and implementation of the information systems in the organizations. It is, therefore, essential that they remain abreast of the latest software development methods and tools while using them. This concise book presents in an abstracted form, the essentials of theory and practice of structured systems analysis and design. It is aimed at getting the concep-tual framework across to the readers and thus aiding in concept implementation. Well-suited for teaching an academic course of one semester in systems analysis and design, the text is also suitable for conducting short term training programmes for software professionals. Armed with these concepts and ideas, the systems analysts will be able to tackle various aspects of systems analysis and design in real life situations.