In more than thirty-five years of consulting, I have found that, at the upper echelons of large organizations, natural intelligence differentiates the successful leader from the “also ran.” While you’ll hear debates about the roles of emotional intelligence, vision, and the ability to motivate others, brainpower trumps all. Three main components define what I call Executive Intelligence: Critical thinking, learning ability, and quantitative skills. Of these, critical thinking—that “lick of sense” you hear so much about—is the most important and the least understood.