There are 9 personality types according to the Enneagram theory. This is an excellent introduction and informative discussion of the subject. It has some lighthearted cartoons and after enabling you to decide your type and then helps you to deal with other types.

I wrote yes for everything, but compelling is a strong word. But its very interesting.

This is a wonderfully accessible book about the Enneagram which gives those who want a simple introduction all the information they need.

This book is a really good introduction to the Enneagram system of personality, without getting bogged down in too much analysis. There are some funny and cute cartoons in there, which highlight the key dilemmas involved with being each type, and the way they interact with each other. Might make a good present for someone.