This document provides an overview of embedded systems. It discusses that embedded systems are found everywhere from large airplanes to small smartwatches. An embedded system is defined as a computer system designed to perform one or a few dedicated functions, which is usually embedded as part of a complete device. The document outlines that embedded systems far outnumber traditional desktop computers. It provides examples of the many embedded systems in the average home and car. It also describes the basic components and characteristics of embedded systems including processors, memory, inputs, outputs and real-time functionality. Overall, the document introduces embedded systems and their pervasiveness in devices across many industries.