This book fills the critical need for an in-depth technical reference providing the methods and techniques for building and maintaining confidence in many varities of system software. The intent is to help develop reliable answers to such critical questions as: 1) Are we building the right software for the need? and 2) Are we building the software right? Software Verification and Validation: An Engineering and Scientific Approach is structured for research scientists and practitioners in industry. The book is also suitable as a secondary textbook for advanced-level students in computer science and engineering.