In the early phases of software development, failure information is not available to quantitatively measure reliability of a software product. This book discusses the need and various methods of quantifying the software reliability in early stages. Currently there is no consensus on approaches for reliability analysis of software owing to the challenges in data, modeling and analysis of these systems. In this book, emphasis is given for applicability of software metrics for quantification of software reliability.The book also discusses some of the previous work in this direction. In addition, techniques such as Bayesian Belief Network and expert elicitation were also discussed from the framework of software reliability prediction. This book attempts to establish a link between theory and practice of software reliability methods for any software product