Sensory substitution and augmentation devices are built to try to replace or enhance one sense by using another sense. For example, in tactile-vision, stimulation of the skin driven by input to a camera is used to replace the ordinary sense of vision that uses our eyes. The feelSpace belt aims to give people a magnetic sense of direction using vibrotactile stimulation driven by a digital compass. Fiona Macpherson brings together researchers -neuroscientists, psychologists and philosophers -who are developing these technologies, studying the minds and behaviour of subjects who use them. Sensory Substitution and Augmentation has three specific aims. The first is to present the latest empirical research on sensory substitution and augmentation. Second, philosophers and scientists who adopt a very different approach comment on the empirical work. Their commentaries are often critical of the assumptions of the work, but often they make and call for clarifications, suggest extensions to the work, or comment on features of the application of the work that the original authors do not. This is one reason why Sensory Substitution and Augmentation is more than simply a collection of papers on the same topic. Finally, philosophers look at the nature of sensory substitution and augmentation, tackling issues such as the nature and limitations of sensory substitution, the nature of the sensory experiences, theories of perception, and the potential for these devices to help those people with disabilities, in part due to future amendments of the devices that are suggested. Throughout, there is a particular focus on the nature of the perceptual experiences, the sensory interactions, and the changes that take place in the mind and brain over time that occur while using and training to use these technologies.