Any combination of a computer processor, computer memory and input/output devices which plays a dedicated role in a much larger electrical or mechanical system is defined as an embedded system. These systems often have real time computing constraints. Embedded systems can range from small and portable devices like digital watches to large and stationary installations such as programmable logic controllers and traffic light controllers. Some of the factors which affect their design and usability include the user interface, processor design and peripherals. Embedded software architectures can be broadly classified into interrupts controlled systems, simple control loop, cooperative multitasking, multi-threading, microkernels and monolithic kernels. The various sub-fields of embedded systems along with the technological progress that have future implications are glanced at in this book. It is an essential guide for both academicians and those who wish to pursue this discipline further.