We have recently seen a renewal of interest in the field of software architectures. This has happened within the object-oriented community - with the emergenceofframe­ works and patterns- but also within a wider context of software engineering- with the concepts of components and component-based development. Work is now pro­ ceeding apace with new developments coming very rapidly. In such an environment it is easy to lose some important ideas; the need for a reflective view on what will be the lasting developments led us to organise a two day seminar in the Open University as a checkpoint in current development. To this end we gathered field-leaders from both industry and academia to lead a lively discussion and exchange of ideas. This book is a result ofa very successful event. From the outset we were not only interested in the discussion of the technical aspects of architectures within software engineering but also on the business and or­ ganisational implications of these approaches. Independentlyof how we may answer the question "Is architecture or component technology the new 'silver bullet'?" we must recognise that an approach based on the techniques presented in this book is a long term investment and requires changes in organisation and a careful consideration ofbusiness implications to be successful.