The evolution of the glass façade is central to the evolution of architecture, as one of the most representative components of modernity. Embodying idealism and cultural expression, the glass envelope is the architectural element that has most significantly captured architects’ imagination, most visibly reflecting the sophistication of new technologies. This book focuses on the main and most immediate contribution of glass to architecture: light. It explores how different forms of glass brought light to our buildings in new spectacular ways, beginning in the mid-19th century, and then taking unprecedented resonance after the oil crisis of 1973, where glass technology also played an active role in the quest for energy efficient façades. It also reveals how architects, engineers and industry invested their skills and imagination to create pioneering projects and experiments. Focusing on critical moments, when glass came to the forefront of architectural thought, the book illustrates how the use of glass was driven as much by changing cultural interests in the manipulation of luminous environments as it was by technological developments.