This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book examines system-level design approaches and associated tools such as Ptolemy and the MathWorks tools, and illustrates them for video applications. It discusses major approaches to specifying and modeling systems, as well as the languages and tools in this domain. The book explores heterogeneous specifications, models of computation and linking multidomain models, requirements on languages, and specialized tools and flows in this area. It outlines the broad field of performance evaluation and sets it in the context of multiprocessor system on chip. The book also discusses dynamic power management approaches, aimed at selectively stopping or slowing down resources, whenever possible while providing required levels of system performance. It shows that state-of-the-art specification languages, tools, and methodologies for processor development used in academia and industry. The book describes the use of standard benchmarks and instruction set simulators to evaluate processor cores.