INTRODUCTION
EARLY CLASSIFICATION OF GALAXIES
DEVELOPMENT OF THE MODERN SYSTEM
- Early Isolation of the Types
The Early Hubble System
Hubble's Major Modification Between 1936 and
1950
Finer Subdivision Along the Sequence
REVISION BY DE VAUCOULEURS
- Extension of the Sequence Beyond Sc
Transition Between Ordinary and Barred
Spirals
The r and s Varieties
Graphical Representation of the
Classification
Additional Features of the de Vaucouleurs
Revision
SELECTED ILLUSTRATIONS OF GALAXY TYPES
- Elliptical Galaxies
Spirals with Thin Filamentary Arms
Spirals with Massive Arms
Transitions Between Sa and Sb
Pure Barred Galaxies
Sdm, Sm, and Im
Ir II Galaxies
Interacting Galaxies
VAN DEN BERGH'S CLASSIFICATION
MORGAN'S CLASSIFICATION BASED ON THE LUMINOSITY
CONCENTRATION OF THE SPHEROIDAL COMPONENT
SYSTEM OF VORONTSOV-VELYAMINOV
COMPARISON OF THE CLASSIFICATION SYSTEMS
SEYFERT GALAXIES, N GALAXIES, AND QUASARS
STELLAR CONTENT RELATED TO TYPE: FORMATION AND
EVOLUTION
REFERENCES
