Nanoporous gold—from an ancient technology to a high tech material. In this chapter, we give an introduction to nanoporous gold and explain the broader background and the origins of the material. In particular, we elucidate the reasons that have made this material one of the prime examples of nanotechnology leading to a large number of various applications. We first give a brief introduction to the material itself followed by a concise review on the element gold, its history, and uses throughout the centuries. We then explain why ‘nano’ in combination with gold evokes novel material characteristics of this element. It is the combination of gold and feature sizes on the nanoscale that lead to the many exciting technological applications highlighted in the different chapters of this book.