The atomic nucleus, consisting of protons and neutrons, is a unique strongly interacting quantum mechanical system that makes up 99.9% of all visible matter. From the inception of gamma-ray detectors to the early 21st century, advances in gamma detection have allowed researchers to broaden their understanding of the fundamental properties of all nuclei and their interactions. Key technical advances have enabled the development of state-of-the art instruments that are expected to address a wide range of nuclear science at the extremes of the nuclear landscape, excitation energy, spin, stability, and mass. The realisation of efficient gamma detection systems has impact in many applications such as medical imaging environmental radiation monitoring, and security. Even though the technical advances made so far are remarkable, further improvements are continually being implemented or planned.