Book excerpt: Providing an overview of the necessary components and the range of applications from light-barriers to high-resolution surface-scanning interferometers, this is a valuable introduction to the technology of optical sensors as well as a reference for experienced practitioners. The first part of the book introduces readers to the basics of sensor principles by describing the most important components that can be found in all optical sensors. Based on this opto-electronic toolbox, the second part then goes on to give numerous examples of optical sensors with respect to their applications.