This book presents the current state of practice and research in the area of software architecture. In addition to detailing critical problems and their possible solutions in the field, the book identifies the gaps between business needs and research results and attempts to provide a bridge between them. Its scope includes theory, processes, technology, and specific examples. It represents: a state-of-the-art snapshot of the best cutting-edge thinking in academia, government and industry concerning software architecture; a summary of current research, case studies and experience reports; and an identification of the problems and proposed solutions in the design, implementation and evolution of software architectures. /LIST This book comprises the proceedings of the First Working Conference on Software Architecture held in February, 1999, in San Antonio, Texas, USA. The conference was sponsored by the International Federation for Information Processing (IFIP) and organized by the Software Engineering Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA. The conference proceedings will be particularly relevant to researchers in the field of software architecture and engineering and to practicing software architects in industry and government.