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 qua-li-ty 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 pro-ducts 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 archi-tectures from the point of view of architecture analysis and describes a ho-lis-tic method for completing the assessment. Case studies and discussions help readers use the approach described in their own projects. This book is addres-sed to professional software architects and developers building or planning to build software product lines. It is also directed to-wards researchers in Software Architectures and Software Product Lines.