Recent advances in information and micro-scale technologies are enabling a new generation of embedded systems that are pervading all aspects of our daily lives. From home appliances to automobiles and aircrafts and from robots to manufacturing plants, computers equipped with sensors and actuators sense the physical environment and respond to it. These are computer systems that are characterized by the blurring of boundaries between the physical and computational worlds. Intelligent transportation systems will make travel faster and safer. Smart robots will explore uncharted and hostile terrain. Mobile sensor nets will perform detailed environmental and pollution monitoring. These are embedded systems that involve multiple modes of operation in uncertain environments, heterogeneous software and hardware components, and distribution across multiple agents. The research field of hybrid systems is aiming at establishing the theoretical foundations for embedded software development. Hybrid system theory is bridging computer science, control engineering, and applied mathematics aiming at the development of formal analysis and synthesis methods for embedded systems.