AbstractJules Bernard Luys, a highly energetic French investigator who made important contributions to anatomopathology, clinical neurology, and psychiatry, discovered the subthalamic nucleus in 1865. Unfortunately, Luys’ description of the nucleus that still bears his name, as well as his highly original insights on the role of this important motor structure, are rarely taken into account in the current thinking about the basal ganglia organization. Thus, we thought it of interest to review Luys’ contribution to our knowledge of the subthalamic nucleus and also briefly examine the other remarkable achievements of this singular figure of 19th century neurology. © 2001 Movement Disorder Society.