Executives often pride themselves on their rational data based approach to achieving business effectiveness. But emotions whether conscious or unconscious often have powerful action tendencies linked to them, and many of them tend to be negative. For example, sadness involves shutting down and anger often involves retaliation or attack. When we are not in touch with our emotions we are less likely to make rational decisions. In fact, we cannot act rationally without full use of our emotions. While the study of cognitive psychology dominated the last half of the past century, the study of emotional regulation will likely dominate much of the current century. Knowledge gained from the scientific study of emotions is likely to have applications for business leaders for decades to come. Emotions are the language of leadership.