My main interest is understanding what is considered to be one of the key aspects of the emergence of modern human behavior – long distance movement of raw material – by instrumentally characterizing archaeological artifacts (in particular obsidians) and geological sources where these artifacts were supposed to have been obtained. Obsidian geochemical studies have been used to address a number of archaeological issues in many parts of the world and have provided evidence, among others, for long distance trade, contacts, and resource utilization. The Horn of Africa, however, lacks such investigations in spite of the fact that there are abundant obsidian artifacts recovered from sites ranging from the Early Stone Age (ESA) to the Neolithic. My work at the MPI-EVA involves the geochemical characterization of both MSA archaeological artifacts and their probable geological sources, a work which is already yielding some interesting insights into the prehistory of the Horn of Africa. Although my main interest is to reconstruct the social dimension of obsidian during the MSA, the obsidian source data generated from my investigation can be used to illuminate aspects of lithic raw material procurement and changes through time, control of raw material and interaction spheres of any time period in prehistory ranging from the ESA to the recent past.