1. INTRODUCTION

2. THE ω Cen SAMPLE

   2.1. The K-Mg Anti-correlation

3. THE METALLICITY DISTRIBUTION

   4.1. Metallicity Dependence

   4.2. Identifying Multiple Populations

5. MULTIPLE POPULATIONS BASED ON N AND C

6. THE STELLAR POPULATIONS OF ω Cen

   6.1. An Overview of the Seven Populations

7. SUMMARY