The first edition of this book established itself as the leading book on this topic of growing importance. It was critically acclaimed (recipient of the Software Development Magazine Productivity Award) and widely embraced by customers. The second edition maintains the goals of the first edition: to define and explain software architecture, and to demonstrate, through real-world case studies, its importance for software system design. The added goals of the second edition are to bring the content up-to-date with significant developments in the understanding and practice of software architecture in the past five years. These developments include advances in architecture analysis, design, reconstruction, and documentation—advances in which the authors, through their work at the Software Engineering Institute (SEI), have played a direct and prominent role.