The results of studying the kinetics of spontaneous (homogeneous) and catalyzed (heterogeneous) crystal nucleation in silicate glass is presented for glasses in the Li2O–SiO2 system. Nucleation is catalyzed via the photosensitive mechanism by adding poorly soluble impurities, shifting the glass composition towards the higher content of one of the components (autocatalysis), and by passing steam through the glass melt. The fundamental characteristics of crystal nucleation are obtained. The composition ranges with the maximum and minimum steady-state crystal nucleation rates are identified. There has been keen interest in the fundamental problems of crystal nucleation and growth in glass due to the development of new glass ceramic materials. The fabrication of these materials is based on the controlled crystallization of glass with tailored compositions, which would be impossible without knowing the general regularities of crystal nucleation and growth in glass. A quantitative description of the experiment is a major challenge when studying the homogeneous and heterogeneous crystal nucleation and amorphization and crystallization processes in glass. In this study, we investigated homogeneous crystal nucleation and the main methods for catalyzing the crystal nucleation for glass in the Li2O–SiO2 system.