Robotics contains elements of mechanical engineering, electrical engineering, and computer science. One of the challenges in reading a robotics text or entering the field as a hobbyist is the variety of concepts and terminology one must know. This book, a "how things work" for the robotics field, provides about 400 brief articles explaining concepts from "acoustic proximity sensor" to "zooming." Some entries are very short; "Guidance System," for example, requires only two sentences and refers to other articles. A longer article like "Logic Gate" is a page and a half long, including a diagram and table. Most topics are technical, but some are philosophical, such as "Jungian World Theory."