Lasers have a wide range of uses, including as precision heat sources for welding, cutting, marking, forming, peening, hardening, and more recently, 3D printing. Precise energy deposition also makes lasers useful tools for research in high-energy-density science, particularly at very short pulse lengths and high peak intensities. In all of the materials-processing applications, the properties of the material and the laser are important. By varying wavelength, power, beam size, or pulse duration, the nature of the interaction can be controlled and fine-tuned.