The senses, or sensory modalities, constitute the different ways we have of perceiving the world, such as seeing, hearing, touching, tasting and smelling. But how many senses are there? How many could there be? What makes the senses different? What interaction takes place between the senses? This book is a guide to thinking about these questions. Together with an extensive introduction to the topic, the book contains the key classic papers on this subject together with nine newly commissioned essays.One reason that these questions are important is that we are receiving a huge influx of new inf