hat lies beyond the intellectual skill and ability of most, but it is also a task that pulls together a maze of a seemingly infinite number of related and interacting details. In this book, Thomas takes the reader away from the trees to look at the wood, making the subject matter accessible by carefully distinguishing between the problem space and the solution space. In a clear and friendly style, he introduces the key aspects of SM&AML and clearly demonstrates the role that SM&AML play in the development process. This is a book that I can highly recommend to my fellow systems architects, engineers and researchers. I find the description of SM&AML follows an intuitive natural flow and thought process, and once you start reading the book, SO will you. Montreal Jens J. Larsen, P.Eng December 2000 Senior Engineer Ericsson Research, Canada Preface Over twenty years ago, a friend of mine, who was working as a systems designer with the successful Ericsson AXE system, complained bitterly that, although they had managed to deliver the first few operational systems to the client's satisfaction, they did not have a clear picture of how everything hung together, in particular how different functions were related to each other. What a tremendous help it would be in managing the evolution of the system, he said, if we had one model that could show us how all functions in the system were related. I was astonished by his remark, since for me, with my background in hardware design and documentation (and some insights into building construction), it was difficult to understand that it was possible to actually design, and successfully implement such a complex sys- tem, without accurate and detailed drawings of its structure and functions. At the time I was busy solving other problems, but the challenge that his remark meant to me, lingered in my mind for the years to come. The AXE system of the 1970s was one of the very first steps on the road of "stored program control" of telecommunication systems, i.e. software control of the s