Photonic Crystals (PCs) are periodic nanostructures that offer unprecedented control of light and have emerged as an interdisciplinary field of research. The goal of this book is to draw the background and map out the frontiers of photonic crystals towards the study of a variety of unusual characteristics of 1-D, 2-D and 3-D PCs using several approaches including discussions based on experimental support, and it also focuses on their prospective scopes. It covers current research advances from around the globe on different features of photonic crystals and demonstrates their applications in design of optical devices, viz., photonic crystal fibers, biochemical sensing, and optical computing. The optical materials covered in this book include dielectric, superconductor, collisional plasma, polymeric colloidal, infiltrated liquid sensor and embedded dye along with material architectures, such as heterostructures, two-dimensional PCs, quasicrystallographic 3-D chiral lattices, holey fibers, and antiresonant reflecting optical waveguide. The book is intended for researchers in the areas of photonic crystals and nanophotonics.