The main site of dust formation is believed to be the cool envelopes around AGB stars. Nearly all AGB stars can be identified as long-period variables (LPVs) with large amplitude pulsation. Shock waves produce by the strong pulsation and radiation pressure on newly formed dust grains drive dusty stellar winds with high mass-loss rates. IR observations of AGB stars identify various dust species in different physical conditions. Radio observations of gas phase materials are helpful to understand the overall properties of the stellar winds. In this paper, we review (i) classification of AGB stars; (ii) IR two-color diagrams of AGB stars; (iii) pulsation of AGB stars; (iv) dust around AGB stars including dusty stellar winds; (v) dust envelopes around AGB stars; (vi) mass-loss and evolution of AGB stars; and (vii) contribution of AGB dust to galactic environments. We discuss various observational evidences and their theoretical interpretations.

Abstract
1. INTRODUCTION
2. CLASSIFICATION OF AGB STARS
    2.1. O-Rich AGB Stars
    2.2. C-Rich AGB Stars
    2.3. S Stars and Silicate Carbon Stars
    2.4. A Catalog of AGB Stars
    2.5. Chemical Evolution
3. IR TWO-COLOR DIAGRAMS OF AGB STARS
4. PULSATION OF AGB STARS
5. DUST AROUND AGB STARS
    5.1. Dust Formation in AGB Stars
    5.2. Optical Properties of Dust Grains
    5.3. Crystalline Dust Grains
    5.4. Dust Driven Winds
6. DUST ENVELOPES AROUND AGB STARS
    6.1. Models for Expanding Dust Shells
    6.2. TheoreticalModels for the 2CDs
    6.3. Models for Non-Spherical Multiple Dust Envelopes
7. MASS-LOSS AND EVOLUTION OF AGB STARS
    7.1. Mass-Loss from OH/IR Stars
    7.2. Evolution to Post-AGB
    7.3. Binary Stars and Dusty Disks
8. CONTRIBUTION OF AGB DUST TO GALACTIC ENVIRONMENTS
9. SUMMARY
REFERENCES

• KYUNG-WON SUH(Department of Astronomy and Space Science, Chungbuk National University) CORRESPONDING AUTHOR