Confederate general "Stonewall" Jackson has been called "one of the greatest military geniuses the world ever saw." However, on critical review of his command decisions during the course of 12 of the 20 battles he fought during the American Civil War, historians have rated his performance as poor. In this investigation, the authors examined the effect of sleep deprivation on Jackson's battle decisions in light of experimental data driving current calls for limiting the duty hours of physicians.