Enneagram is a model of human personality which is principally used as a typology.It definite nine types temperament：
1. The Reformer
2. The Helper
3. The Achiever
4. The Individualist
5. The Investigator
6. The Loyalist
7. The Enthuiast
8. The Challenger
9. The Peacemaker
Sometimes we use the "wing" to make the definition more incorrect.Just like the picture--
And it also be classified Instinctual subtypes which usually called "self-preservation", "sexual" and "social".
No one know who created it,most of people think that it is a old knowledge which can find in history of Pythagoras. But Enneagram is one of the most popular theory on personality.Many company like HP and Coke Cola apply it on HR and it is a hot course in university too.
If you want know which one is your type,It is the test