Revision with unchanged content. The quest for more productive ways of developing high quality software has been ongoing and software product lines promises to improve product quality and the development speed at a fraction of the cost. Common examples of product lines in other areas include mobile phones, cars, consumer electronic devices such as TVs and the like. The products in a product line all share some common features and there are some features that are specific to some products only. Crucial to this approach is the large-scale reuse of the product line software architecture. This book deals with the problem of assessing, analyzing or evaluating product line architectures. It characterizes such architectures from the point of view of architecture analysis and describes a holistic method for completing the assessment. Case studies and discussions help readers use the approach described in their own projects. This book is addressed to professional software architects and developers building or planning to build software product lines. It is also directed towards researchers in Software Architectures and Software Product Lines.