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Table of Contents

• 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