In this paper we briefly discuss the main concept and details of X-ray Lithography, a parallel lithographic technique belonging to the domain of UV lithography (UVL). The main difference lies on its usage of X-ray photons, which having a much shorter wavelength were supposed to provide for a ‘resolution reserve’ for Moore’s law requirements, long after UVL would fail to do so. However, new advances in UVL technology (e.g., Deep UV, projection exposure systems, etc.) had finally won the race and made XRL impractical for large scale industrial applications in integrated circuit (IC) manufacturing, but some of its characteristic properties still hold advantages in certain techniques (e.g., LIGA).