Аннотация:The glassy state of matter is briefly analysed with an emphasis on long-term stability andimpediment of relaxation to a thermodynamically stable crystalline structure. Melt quenching as the basic method of glass formation is discussed and the kinetic conditions for vitrificationdescribed. Structural, microscopic and energetic criteria for glass formation are considered the notions of glass formers, intermediate and modifiers being explained. The glass transition is briefly analysed from the view point of topological rearrangements of the bonding system that lead to different properties of glasses and melts. The cooling-rate dependence of glass transition temperature is also discussed.