Sensors for measuring physical quantities such as temperature, pressure, level, or rotational speed play an important role in many areas of technology and science. The constantly growing market for such sensors, the desire for more cost-effective manufacturing options, and the demand for sensors for novel applications have triggered a global sensor boom in recent years. This is reflected not only in increased development activities but also in the rising number of contributions in scientific journals and at conferences, as well as in various market forecasts. Chemical sensors are often included in these activities, which is not always straightforward. Recently, the development of sensors is frequently in the hands of semiconductor experts, physicists, or even physiologists for technological reasons.