This issue of ECS Transactions focuses on those characteristics of nanoscale materials that relate to their luminescence properties. Topics covered include the effects of quantum confinement, the role of surface states, loss mechanisms, methods to improve luminescence efficiency, bulk vs. nanoparticle luminescence, the role of phonons in nanomaterials, nanophosphors for biophotonics and biomarkers, nanoparticles for light emitting diodes, and nanophosphors for traditional phosphor applications.