Semiotics is the science of signs: graphical, such as pictures; verbal (writing or sounds); or others such as body gestures and clothes. Computer semiotics studies the special nature of computer-based signs and how they function in use. As computers have become a feature of daily life, work and education, the design of the interface has become of prime importance, so that the machines can be used quickly and easily. Systems are more easily learned if the designer takes his or her departure point in the established sign usage of the users, for example, their language, and conscious use of signs in designs improves the benefits and ease of using computers. This book is based on ten years of empirical research on computer usage in work situations and contains material from a course taught by the author. It introduces basic traditional semiotic concepts and adapts them so that they become useful for analysing and designing computer systems in their symbolic context of work. It presents a novel approach to the subject, rich in examples, in that it is both theoretically systematic and practical. The author refers to and reinterprets techniques already used so that readers can deepen their understanding. In addition, it offers new techniques and a consistent perspective on computer systems that is particularly appropriate for new hardware and software (e.g. hypermedia) whose main functions are presentation and communication. This is a highly important work whose influence will be wide and longlasting.