Virtual Reality (VR) offers the potential to develop human testing and training environments that allow for the precise control of complex stimulus presentations in which human cognitive and functional performance can be accurately assessed and rehabilitated. However, basic feasibility and human issues need to be addressed in order for this technology to be reasonably and efficiently applied in clinical psychology. The book, written in a scholarly style, will provide rationales for virtual reality's applicability in clinical psychology. We will review the relevant literature regarding theoretical and pragmatic issues for these applications, and provide a description of ongoing work developed world-wide. The topics directly involve critical issues for clinicians, designers and users, and will be discussed with scientific competence without neglecting clarity and empirical cases with suggestions for actual use. The book is divided in three main sections: VR in clinical psychology: opportunities and challenges, VR in treatment of phobias and VR in clinical assessment and therapy.