Current advances in nanoparticle technology promise exciting possibilities in our fight against cancer. Gold nanomaterials are a class of inorganic nanoparticles that possess unique optical properties which can be harnessed for the diagnosis and therapy of cancer. This book discusses the optical theory, synthesis, characterization, and surface functionalization of gold nanostructures for use as optical probes in light scattering-based optical imaging. Their optical properties in vitro and in tissue phantom models, as well as their efficacy as contrast agents in small animal tumor imaging are examined. The potential use of these gold nanostructures in photothermal therapey in combination with conventional photodynamic therapy is also discussed. The content in this book should provide good insights on how gold nanomaterials can potentially be used to facilitate early detection and treatment of pre-cancers through expression profiling of molecular markers, and should be especially useful to academics, clinicians and research professionals who have an interest in cancer nanotechnology.