Textual notation-based approaches have been used for their formal syntax and semantics to represent system features and implementations. But these approaches are still weak in the mixing features (conceptual level) and classes (physical level) that guarantee smooth and automatic configuration generation for software releases. In this book, we will enhance SPL process by defining meta-features that captures the most important characteristics of feature modelling concepts, and classifying these features according to their functionalities. We will allow mixing class and feature concepts in a simple way using class interfaces and inherent features for smooth move from feature model to class model. SPL process will be enriching with a textual design and implementation methodology mixing class and feature model in new way. This methodology allows class model to be declared in a way that reflects features model concepts with consistent mixing with feature model. It enhances configuration generation process to be simpler, more coherent and complete.