Glass transitions are usually thought to be the province of supercooling liquids which fail to crystallize, but this description in a number of ways underrates their importance to condensed matter physics. Firstly, some of the most interesting glass transitions occur in phases that have never "seen" the liquid state until they pass through the glass transition during heating, and others never see it at all, if we allow the term "glass transition" to refer to the breaking and restoring of ergodicity in a condensed phase of interest. This paper focuses on using data on a glass transition of the latter type which occurs in the cooling and reheating of a simple system comprising two similar metal atoms, Co and Fe in a 1:1 mixture, to provide an easily understood example of a glass transition in a system in which both the kinetics and excitation thermodynamics lie at the "strong" extreme of the "strong-fragile" spectrum of liquid formed glass behaviour and the glass transition is the precursor to a lambda transition at higher temperatures. From this starting point, we then consider the relation between glass transition behaviour of inorganic (SiO2, BeF2) and molecular (H2O) network glasses, and then their mixtures with ideal solution-forming second components. This provides a common basis for the observed precipitation from alkali silicates of almost pure SiO2 on the one hand, and first order transformation of aqueous solutions to almost pure low density amorphous water, on the other.
