The last decade has been one of great progress in the field of software architecture research and practice. Software architecture has emerged as an important subdis- pline of software engineering. A key aspect of the design of any software system is its architecture, i. e. the fundamental organization of a system embodied in its com- nents, their relationships to each other, and to the environment, and the principles guiding its design and evolution (as defined in the Recommended Practice for Arc- tectural Description of Software-Intensive Systems -- IEEE Std 1471-2000). - The First European Workshop on Software Architecture (EWSA 2004) provided an international forum for researchers and practitioners from academia and industry to discuss a wide range of topics in the area of software architecture, and to jointly f- mulate an agenda for future research in this field. EWSA 2004 distinguished among three types of papers: research papers (which describe authors' novel research work), experience papers (which describe real-world experiences related to software architectures), and position papers (which present concise arguments about a topic of software architecture research or practice). The Program Committee selected 19 papers (9 research papers, 4 experience - pers, and 6 position papers) out of 48 submissions from 16 countries (Australia, B- zil, Canada, Chile, Finland, France, Germany, Italy, Japan, Korea, The Netherlands, Spain, Switzerland, Turkey, UK, USA). All submissions were reviewed by three members of the Program Committee.

The last decade has been one of great progress in the field of software architecture research and practice. Software architecture has emerged as an important subdis- pline of software engineering. A key aspect of the design of any software system is its architecture, i. e. the fundamental organization of a system embodied in its com- nents, their relationships to each other, and to the environment, and the principles guiding its design and evolution (as defined in the Recommended Practice for Arc- tectural Description of Software-Intensive Systems -- IEEE Std 1471-2000). - The First European Workshop on Software Architecture (EWSA 2004) provided an international forum for researchers and practitioners from academia and industry to discuss a wide range of topics in the area of software architecture, and to jointly f- mulate an agenda for future research in this field. EWSA 2004 distinguished among three types of papers: research papers (which describe authors' novel research work), experience papers (which describe real-world experiences related to software architectures), and position papers (which present concise arguments about a topic of software architecture research or practice). The Program Committee selected 19 papers (9 research papers, 4 experience - pers, and 6 position papers) out of 48 submissions from 16 countries (Australia, B- zil, Canada, Chile, Finland, France, Germany, Italy, Japan, Korea, The Netherlands, Spain, Switzerland, Turkey, UK, USA). All submissions were reviewed by three members of the Program Committee.