Design of System on a Chip is the first of two volumes addressing the design challenges associated with new generations of the semiconductor technology. The various chapters are the compilations of tutorials presented at workshops in Brazil in the recent years by prominent authors from all over the world. In particular the first book deals with components and circuits. Device models have to satisfy the conditions to be computationally economical in addition to be accurate and to scale over various generations of technology. In addition the book addresses issues of the parasitic behavior of deep sub-micron components, such as parameter variations and sub-threshold effects. Furthermore various authors deal with items like mixed signal components and memories. We wind up with an exposition of the technology problems to be solved if our community wants to maintain the pace of the ‘International Technology Roadmap for Semiconductors’ (ITRS).