nd Welcome to the proceedings of PERVASIVE 2004, the 2 International C- ference on Pervasive Computing and the premier forum for the presentation and appraisal of the most recent and most advanced research results in all - undational and applied areas of pervasive and ubiquitous computing. Consi- ring the half-life period of technologies and knowledge this community is facing, PERVASIVE is one of the most vibrant, dynamic, and evolutionary among the computer-science-related symposia and conferences. The research challenges, e?orts, and contributions in pervasive computing have experienced a breathtaking acceleration over the past couple of years, mostly due to technological progress, growth, and a shift of paradigms in c- puter science in general. As for technological advances, a vast manifold of tiny, embedded, and autonomous computing and communication systems have st- ted to create and populate a pervasive and ubiquitous computing landscape, characterized by paradigms like autonomy, context-awareness, spontaneous - teraction, seamless integration, self-organization, ad hoc networking, invisible services, smart artifacts, and everywhere interfaces. The maturing of wireless networking, miniaturized information-processing possibilities induced by novel microprocessor technologies, low-power storage systems, smart materials, and technologies for motors, controllers, sensors, and actuators envision a future computing scenario in which almost every object in our everyday environment will be equipped with embedded processors, wireless communication facilities, and embedded software to perceive, perform, and control a multitude of tasks and functions.