Within the past several years we have witnessed the emergence of a new class of materials which provide capabilities along a new dimension in the control and manipulation of light. These materials, known as "photonic crystals," are viewed ideally as a composite of a periodic array of macroscopic dielectric scatterers in a homogeneous dielectric matrix. A photonic crystal affects the properties of a photon in much the same way that a semiconductor affects the properties of an electron. Consequently, photons in photonic crystals can have band structures, localized defect modes, surface modes, etc. This new ability to mold and guide light leads naturally to many novel applications of these materials as optoelectronic components. An introductory survey including recent exciting developments in the field of photonic crystals is presented.