The field of photonic band gap (PGB) materials, also called photonic crystals, is one of the most exciting new areas in physics and engineering. The materials play a unique role in controlling the propagation of electromagnetic waves, and innovative ways to manipulate such waves can have a profound influence on science and technology. The present book provides an excellent survey of the field of photonic crystals, random lasers and light localization, covering theoretical and experimental aspects as well as applications. The introductory lectures are accessible to non-specialists. New fabrication techniques and structures are presented with either dielectric or metallic components. Microwave, far-IR and optical applications are discussed (filters, mirrors, switches, waveguides, bends, splitters, antennas, etc.). Transmission, band structure and finite difference-time domain techniques are presented. Reviews of the random laser area and light localization are also presented.