Nanoscale science and engineering, or "nanotechnology" as it is commonly known, has been a fundamental component of glass technology for hundreds, if not thousands of years. Numerous examples can be found where our understanding of glass at the nanoscale level has proved transformational in the fabrication and application of this material. Amount these are band theory, photosensitivity, ligand field theory, glass structure, microcrack theory, amorphous phase separation, controlled crystallisation, and surface modification. Modern applications of glass in such diverse fields as energy, medicine, electronics, photonics, and communications are critically dependent on our awareness and appreciation of the intrinsic connections between glass and nanotechnology. Starting at the low end of the nanoscale, this article reviews fundamental aspects of these connections with the intent of drawing attention to their role in obth contemporary and future glass science and engineering. The article shows how many of the most useful and interesting behaviours of glass are born at the nanoscale, even when initially not noticed.
