This is a very extensive research work on the framework and methodology to improve software architecture and hence software development by using QuaDRA (short for quality-based co-development of requirements and architecture). The work emphasizes the co-development of the requirements and the software architecture, as illustrated by Figure 1.1 in the book. This diagram presents a summary of the interactions between the problem space and the solution space, which the author calls the twin peaks. There are eight phases of this framework divided between the twin peaks as shown, and the phases interact with each other via defined paths between the problem peak and solution peak.

Alebrahim identifies the primary audience of the book as practitioners such as software engineers working in the areas of requirements engineering and software architecture design--particularly novices and less-experienced software engineers. In my opinion, the more appropriate audience is researchers who aim to investigate the relationship between requirements engineering and software architecture and how the activities in each phase restrict the scope of consideration in the other phases.

An important tool for understanding the complex framework and methodology is the use of case studies. The book offers smart grid applications, a sunblind example, and an alarm system as case studies. Smart grid is a real-life application to serve utilities customers in the EU in general, and Germany specifically. The stated requirements are well documented; that is why this application is used extensively to illustrate the application of QuaDRA. A more concise case study can be found in [1]. Unfortunately, since the QuaDRA framework methodology is laid out in eight phases (from chapters 4 to 11), readers must dig into many different places to get a complete picture on how it is applied in the case studies. I found at least nine different sections throughout the book that refer to how the case study is applied by the QuaDRA framework. Therefore, an extensive index is a needed improvement, as it would allow readers to dig through this large research report to get to the proper sections.

The author uses chapter 3 to develop research on the various methodologies to come up with the list of criteria to evaluate the effectiveness of QuaDRA. Then, she uses this list to evaluate QuaDRA in chapter 12. I would have let readers come up with their own conclusions to see if the QuaDRA framework met the evaluation criteria. In chapter 13, the author introduces the concept of a software product line (SPL) and SPL engineering (SPLE) as a way to extend the QuaDRA framework to capture the common security and performance requirements in the SPL. The goals are to reduce development costs, time to market, and maintenance of the software, and to enhance productivity and quality. The author concludes in chapter 14 by providing a summary and the areas for future research and development.

However, I do want to point out that from my own experience with the operation of software applications on the web, especially those that involve user (human) interactions and new domains that require brand new developments such as blockchain and crypto currencies, the quality and operations requirements seldom meet the expectations of the perceived evaluation criteria.