Femtosecond lasers have been considered as a promising tool for micro/nano-scale patterning of various materials. The primary focus of the book is to provide in depth ideas about the fabrication of various structures including micro/nano-holes, micro/nano-gratings, self-organized nanogratings, nanocones, micro/nano-ripples, spherical-shaped nanostructures, and ring-shaped micropatterns in a variety of materials. These kinds of micro/nano-structures have definite applications in photonics/optical devices,... This book describes the fundamental concepts of lasers, laser processing technologies, recent advances in forming a variety of micro/nano-metric structures in glasses & metals and their potential application areas. A comparative study among various material processing technologies have been discussed: lithographic technologies, vapor deposition technologies, and laser processing technologies. The fundamental concepts of femtosecond laser-material interactions are also discussed.