The book provides a comprehensive overview of the physical principles, functions, and applications of sensors. It is organized according to the areas of application for sensors and illustrates their use through typical examples. Measurable quantities that can be captured by sensors include mechanical, dynamic, thermal, as well as electrical and magnetic measurements. Additionally, optical and acoustic sensors are also discussed in detail regarding their applications in the book. The sensor signals are recorded, processed, and converted into control signals for actuators. Such sensor systems are also presented.