Daniel Goleman is the guru of emotional intelligence (EI).
He has written that IQ and technical skills are important, but emotional intelligence is the sine qua non of leadership. Writing in the Harvard Business Review of 1998, Goleman listed five attributes of emotional intelligence that are known to enhance leadership effectiveness.
Self-awareness - knowing one's strengths, weaknesses, drives, values, and impact on others
Self-regulation - controlling or redirecting disruptive impulses and moods
Motivation - relishing achievement for its own sake
Empathy - understanding other people's emotional makeup
Social skill - building rapport with others to move them in desired directions
Read Goleman's HBR article. (512 KB)