Three-dimensional (3D) laser micro-fabrication has become a fast growing field of science and technology. The very first investigations of the laser modifications and structuring of materials immediately followed the invention of the laser in 1960. Starting from the observed photomodifications of laser rod materials and ripple formation on the irradiated surfaces as unwanted consequences of a high laser fluence, the potential of material structuring was tapped. The possibility arose of having a highly directional light beam, easily focused into close to diffraction- limited spot size, and with the arrival of pulsed lasers with progressively shorter pulse durations, the field of laser material processing emerged. Understanding the physical and chemical mechanisms of light–matter interactions and ablation (from lat. ablation, removal) at high irradiance began the ever widening number of scientific and industrial applications.