When examining glass evidence, forensic scientists can be asked to reconstruct a course of events (modus operandi) or to associate broken glass found at a crime scene with material recovered from a victim or a suspect. We will show how glass evidence has been assessed and interpreted. First, we will discuss the preassessment of the case and the importance of establishing working propositions before looking at the physical evidence. Second, we will continue with the comparison of measurements (refractive index and elemental analysis) and the interpretation of the results. We will cover the likelihood ratio approach and others. Surveys on parameters such as transfer, persistence and glass recovered as background will be presented. We will conclude with a brief presentation of the software available.