Globular Clusters

1. Introduction 1.1 Galactic Globular Clusters 1.2 Extragalactic Globular Clusters 2. Physical Parameters for Globular Clusters 2.1 Globular Cluster HR diagrams 2.2 Globular Cluster ages 3. Chemical Composition of Globular Clusters 3.1 Helium content of Globular Clusters 3.2 Metal content of Globular Clusters 3.3 Abundance trends 3.4 Metal content, primitive halo and stellar evolution 4. The Second Parameter Problem 5. Globular Clusters in the Galaxy 5.1 Globular Clusters and the halo 5.2 Structural parameters of Globular Clusters 6. Special problems in Globular Clusters 6.1 X-ray clusters 6.2 Final fate of a Globular Cluster 6.3 The Globular Clusters in the Magellanic Clouds 7. Conclusions