A comprehensive review of the biochemical organization of the malignant astrocytoma is presented. The review is intended for neurosurgeons. It outlines the metabolic flow of events beginning with energy and substrate utilization, followed by structural components (protein, lipids, etc.) and tumor cell secretory products, and ending with nucleic acid synthesis. Cellular pH, tumor-induced cerebral edema, tumor blood flow, and tumor necrosis are also considered.