Empirical validations of software metrics are used to predict software quality in the past years. This book provides a review of empirical studies to predict software fault proneness with a specific focus on techniques used. It highlights the milestone studies done in this area with statistical techniques and metrics. Work done in the field of software fault prediction studies has been elaborated while focusing on statistical techniques and their usage to predict fault proneness. This book emphasizes on more use of class level metrics and statistical techniques to ensure better software quality.