This text provides a practically based introduction to the tools and techniques of computer systems analysis and design. The notation and terminology used is compatible with the latest version of the official UK government method, SSADM version 4.2+, but the order and delivery has been simplified to make it suitable as a first text in the subject for students on computing, information systems and business studies degrees, especially those on modular courses. To emphasise the practical aspects of the topic, reference material and case studies are supported by an independent example, so that teaching and learning activities can progress independently but in parallel. This allows the material to be used by students and lecturers to support more advanced practical courses, especially where group activities and role playing are involved. In addition, advice on professional practice and common skills are made where appropriate throughout the text.