Obsidian provenance research has been one of the most productive programs of archaeological science in recent years. Obsidian characterization has been successful because most sources of obsidian are homogeneous, several analytical techniques are available, and the number of sources is limited to a few geographic regions. Geochemical data from obsidian artifacts can be compared with those from known sources to indicate the provenance for each artifact and may also be used to indicate the presence of unknown geological sources. Archaeologists rely on the data from obsidian to reconstruct long-distance exchange/trade relationships and the movement of prehistoric peoples through time. Geologists study obsidian to understand the processes of magma development and flow. Chemists are interested in improving the methods of obsidian characterization and their accuracy and precision. Because the archaeologists, geologists, and chemists who study obsidian have different objectives, it is essential that those involved understand each another's frame of reference. An appreciation of the geologic processes, analytical methods, and archaeological questions and how to integrate these effectively is a prerequisite to successful implementation of obsidian provenance research.