The book is basically concentrated on the safety metrics for software safety in safety-critical computer systems. The writings can be useful for students and researchers working in the field of software safety. It should also serve as a book of reference in the use of safety metrics in all phases of software development life cycle for software safety in safety-critical computer systems. The book started with a discussion of real life software-related accidents across various key industrial sectors. It highlighted the major limitations in the development of safety-critical systems, the limitation of general purpose software development life cycle, the limitations of traditional software models and the limitation of safety assessment and evaluation of safety-critical systems.