Microcontrollers are key components in many of the electronic products we use every day, including consumer electronics, automobiles, industrial manufacturing equipment, robots, smart buildings, and medical devices. In this issue, we consider microcontrollers and embedded systems in the context of the ever-expanding Internet of Things.◦ We kick things off with a short reintroduction to microcontroller technology (p. 6). In “What’s a Microcontroller?” I describe the differences between microcontroller and microprocessors and clarify some common misconceptions about these amazing devices.