Describes the "decentralized resource exploitation, manufacturing and exchange network" associated with obsidian mines near Teotihuacán during the classic period. Detailed, but somewhat conjectural, picture of the mining, manufacturing, "marketing" system. Maps somewhat obscure. Emphasizes the importance of such "nonsubsistence production and exchange...in the evolution of this first Mesoamerican civilization". His thesis is roughly that monopoly on obsidian blade production was an important factor in Teotihuacán's political dominance of Central Mexico. Later work (Clark, 1986) suggests he overestimates the importance of obsidian exploitation in the Teotihuacán economy.