Gold occurs in many settings, but the dynamic nature of Earth's crust means overlapping and overprinting deposit styles are common. Characterization of mineralization from an early stage becomes important, particularly where the mineralization is complex, in order to maximize exploration and project development success and mining productivity. Various techniques are used at different stages of a project to characterize gold deposits. This Special Publication offers a cross-section of some specific techniques used to investigate a variety of gold deposit types. The papers highlight both the breadth of the available techniques and their utility in deposit characterization, but also the many significant remaining questions and problems related to the exploration and research of gold deposits. Several papers include suggestions of avenues for fruitful further research, including a paper discussing a new approach to classifying orogenic gold deposits, and a paper describing archaeological applications of natural gold analyses.