Embedded and ubiquitous computing systems have considerably increased their scope of application over the past few years, and they include nowadays also mission- and business- critical scenarios. The advances call for a variety of compelling issues, including dependability, security, quality-of-service, modeling, autonomy, middleware support, new applications, real-time, development techniques, etc. This Special Issue is based on innovative ideas on embedded and ubiquitous systems discussed during the 6th IFIP Workshop on Software Technologies for Future Embedded and Ubiquitous Systems (SEUS), held in Anacapri, Capri Island (Italy), in October 2008. SEUS is a flagship event of the IFIP Working Group 10.2 on embedded systems which brings together experts in the field of embedded and ubiquitous computing systems with the aim of exchanging ideas and advancing the state-of-art about the above mentioned issues. Selected papers have been invited out of the 38 papers published in the SEUS 2008 proceedings. Authors of invited papers were required to enrich their work with substantial new material with respect to the original SEUS contributions. Rigorous review of received submissions led to the selection of 12 high quality manuscripts, included in this Special Issue. The Special Issue is conceptually divided into three sections, each of them composed of four papers. The first section is about “Middleware and Applications”. Especially in ubiquitous and distributed embedded systems, middleware is a vital system part enabling various functions and features for the designated applications. The first paper of this section entitled “Exploring Delay-Aware Transactions in Heterogeneous Mobile Environments”, authored by N. Suri et al., deals with transaction handling for database, banking or stock applications on mobile embedded devices. It investigates the impact of typical mobile perturbations on transaction handling and the appropriate design of mobile transactions. The second paper called “Multi-hop Multi-path Cooperative Connectivity Guided by Mobility, Throughput, and Energy Awareness: a Middleware Approach”, and authored by A. Corradi et al., also targets mobile devices. Here, new middleware concepts to achieve best possible tradeoffs between mobility, throughput and energy consumptions are researched. The third paper named “CARISMA – A Service-Oriented, Real-Time Organic Middleware Architecture”, authored by U. Brinkschulte et al., focuses on the aspect of self-organization in middleware for embedded and ubiquitous systems with real-time properties. Service agents are introduced as compact and smart entities to realize self-organisation, self-configuration, self-healing, etc. features well known in biology. The final paper of this first section is entitled “A Comparison of GIS Architectures for Mobile Indoor Location-based Services”, authored by C. Prehofer et al. It is an experience report on building a geographic information system for indoor applications. As a very interesting aspect, the system was build by combining open source software with novel research prototypes. All four papers of this section represent leading edge research in the field of ubiquitous and distributed embedded systems. The second section addresses the “Modeling, Management and Evaluation of Non-Functional Properties”. The evaluation and fulfillment of non-functional properties, such as dependability, security, and quality of service, is widely recognized as a challenging objective for the development of computer systems in general. This also applies to future embedded and ubiquitous systems, where this field is still unexplored. The section presents four cutting edge research papers on this topic. The first paper, entitled “QoS Perceived by Users of Ubiquitous UMTS: Compositional Models and Thorough Analysis”, authored by A. Bondavalli et al., provides a thorough QoS analysis of a dynamic UMTS network by adopting a compositional modeling approach based on Stocastic Activity Network (SAN) formalism. Authors also investigate the impact of users’ mobility on the selected QoS indicators by combining the SAN modeling approach with an ad-hoc mobility simulator. The second paper of the section is entitled “Fault and Error Containment of Gateways in Distributed Real-Time Systems”, and it is authored by R. Obermaisser. The paper investigates the use of gateways, normally used to compose large embedded computer systems out of heterogeneous clusters, to tackle with common mode failures that could be induced by the propagation of faults between clusters. The third paper named “An Overview of VeryIDX – A Privacy-Preserving Digital Identity Management System for Mobile Devices”, authored by E. Bertino et al., deals with privacy-preserving issues in future mobile ubiquitous systems, which can easily be the target of several security attacks. The paper presents an approach to secure the management of user identity attributes trough the definition of an innovative cryptographic primitive. The final paper of this section, authored by M. Cinque et al., is entitled “Modeling and Analyzing the Dependability of Short Range Wireless Technologies via Field Failure Data Analysis”. .......