Interactive systems are growing in the last decade because of the amount of fields in which this kind of application can be used as a test bed to experiment in medicine, training, education, and so on. book highlights the knowledge of several researchers in the field of interactive systems to offer an overview of the different parts of the environment that must be taken into account to develop a quality interactive system from the software engineering discipline. The book is oriented to developers of interactive systems, as well as researchers in the field of virtual environments. This book will be an important pillar in the way this kind of software will be developed.