Micro-Pattern Gas Detectors (MPGDs) are a family of gas detectors with tiny structures as their fundamental building blocks. The essential operating principle that MPGDs share with all gas detectors is as follows: radiation induces ionization within the gas, leading to the separation of electrons and ions in an electric field. Subsequently, electrons generate additional electron-ion pairs through an avalanche process within a region featuring a high electrostatic field, creating a strong, easily detectable signal. For many years, the most common approach to designing gas chambers was to use thin wires. However, these days, MPGD technology has matured to provide numerous well-optimized structures. Moreover, the popularity and success of MPGD technology have paved the way for many applications beyond high-energy and nuclear physics experiments. During the seminar, MPGD technology will be introduced, with a particular emphasis on Gas Electron Multiplier (GEM) detectors. The presentation will cover MPGDs' and GEMs' working principles, features, and various applications.