The papers presented in this special issue, "Glass Science and its Applications", cover the physics and chemistry of conventional glasses, sol gel glasses and glass ceramic materials as used in technological and biomedical applications; for example, the first paper describes the optimization of ormosil glasses for luminescence-based dissolved-oxygen sensor applications. Here, the main aim was to prepare and evaluate various sol gel film compositions in order to identify those most promising for oxygen sensing.The physical, thermal, structural and spectral properties of rare-earth ion-doped boro-fluoro-phosphate glasses are reported in the second paper. In the third paper, splicing and coupling losses in hollow-core photonic crystal glass fibers were discussed. In the following paper, the influence of Fe2O3 in lithium bismuth borate glasses is studied in order to characterize the geometry of the structural units of the glass network and understand the influence of Fe2O3 upon the ac conduction and dielectric properties. In the fifth paper, structural and optical analyses of rare-earth ion-doped LiNbO3 ceramic powders is reported. In paper six, two cases of the application of novel composites based upon glass-reinforced hydroxyapatite in the treatment of human intrabony periodontal angular defects are described; showing that this modified calcium phosphate promoted rapid new bone formation in vivo.This special issue will therefore be of great interest to those searching for a general overview of glass science and its application in various fields.