Neurospectroscopy measures a neuronal marker, energy and redox state, specific fuels of tissue respiration, maturation, and possibly myelination. It provides diagnostic patterns of altered neurochemistry. Current clinical uses range from intensive care in neonates to dementia in the elderly and include tumor and stroke management, prognosis in hemorrhage and trauma, white matter, inflammatory diseases, and AIDS. Inborn errors, metabolic and systemic diseases, subclinical hepatic encephalopathy, hyponatremia, and "coma" have been elucidated. Automation, single-voxel MRS, chemical shift imaging, quality control, and outcome analyses are discussed. With no remaining impediments to clinical use, neurospectroscopy has changed the way we look at diseases of the brain.