This book is the sixth in the ChDL (Chip Design Languages) series. Year 2004 has seen many efforts in the ?eld of electronic and mixed technology circuit design languages. The industry has recognized the need for system level design as a way to enable the design of the next generation of emb- ded systems. This is demonstrated by the "ESL Now!" campaign that many companies are promoting. This year has also seen many interesting st- dardization efforts for system level design, such as SystemC TLM (http: //www. systemc. org/) for transactional level modeling with SystemC, AU- TOSAR (http://www. autosar. org/) for automotive embedded system - plications, or SPIRIT (http://www. spiritconsortium. org/) for IP int- change. In the ?eld of modeling languages, the Model Driven Architecture of the OMG (http://www. omg. org/mda/) has given rise to model driven en- neering, which is a more general way of software engineering based on model transformations. As embedded systems are more and more programmable and as the design abstraction level rises, model driven methodologies are also c- sidered for electronic system level design. In this context, the OMG has - cently published a call for propositions for a UML 2. 0 pro?le for Modeling and Analysis of Real-Time and Embedded systems (MARTE). The constraints on the design process of these next generation embedded systems are considerable: Real-time, power consumption, complexity, mixed technology integration, correctness, time to market, cost, ...