Essential hypertension is commonly “neurogenic,” ie, blood pressure elevation is initiated and sustained by activation of the sympathetic nervous system. Essential hypertension in normal-weight persons is characterized by the activation of sympathetic outflow to the heart, kidneys, and skeletal muscle vasculature, and by increased firing rates in individual sympathetic nerve fibers, with multiple firing salvoes within a cardiac cycle. Obesity-related hypertension differs in two ways: (i) it excludes the cardiac sympathetic outflow; and (ii) it possesses a single-fiber mechanism of sympathetic activation, with recruitment of previously silent fibers, firing at a normal rate. This article looks at the pathophysiological, clinical, therapeutic, and prognostic implications of these variants of essential hypertension...