Emotional intelligence is the inner capacities that let us create optimal relationships with ourselves and others. The skills includes using thoughts, feelings, and actions to build self-knowledge, self-management, and self-direction.
-Josh Freedman

Where IQ is a fixed capacity for processing cognitive information, EQ is a set of learnable skills for making great decisions, living in integrity, and connecting with others.
IQ and EQ are complementary parts of a whole and healthy person. Great intellect does not diminish emotional capacity, and "emotionality" is not at odds with rational thought. People used to see these at odds, but one of the great contributions of modern neuroscience is the realization that emotion and cognition actually work together. In fact, I'd go so far as to say that emotion is the way to learning.
If I had to choose to live in a country full of people with one dominant, I'd choose higher EQ. People with high IQ and low EQ do not function well. However, the reverse is not true -- there are phenomenally successful people with IQs of 110; I will bet they have high EQs.
-Josh Freedman

The concept developed over the last 30 years, with contributions by many authors, researchers, and educators. In 1995, Daniel Goleman's book, Emotional Intelligence, shared the work of many people and brought the concept mainstream. In the book, he talks about Peter Salovey and Jack Mayer (the people who "invented" the science of EQ), Antonio Damasio (a groundbreaking neuroscientist), and others -- he even talks about our Self-Science curriculum. So while Dan did not invent EQ, he played an incredibly important role in bringing it to the public attention.
Damasio's Descartes Error, Mayer and Salovey's Emotional Development and Emotional Intelligence, Cooper and Sawaf's Executive EQ, McCown's Self-Science, Claude Steiner's Emotional Literacy, Candace Pert's Molecules of Emotion, Orioli and Cooper's EQ Map, and Reuven Bar-On's EQ-i are all seminal publications in the field.
- Josh Freedman

There are intrapersonal (within yourself) and interpersonal (between people) skills; because inner capacities appear when we relate to others, there is not a clean separation. That said, some skills that are particularly important in relationships are:

Emotionally intelligent adults make better decisions, they live with integrity, they use their emotions as a source of energy and direction, then are more effective at solving problems, they collaborate better, they are more effective leaders, better spouses, and more conscious parents. Interestingly, they are not always "happier" -- they are less depressed, but more aware of both comfortable and uncomfortable feelings.
-Josh Freedman, 2002