1. Introduction

2. Observation and Analysis

3. General Properties
3.1. Distribution of Superhump Periods
3.2. General Tendency in Period Variations
3.3. Transition to a Shorter Period
3.4. Global Period Derivatives
3.5. Period Derivatives during Stage B
3.7. Superhump Periods during Stage A
3.8. Difference Between Different Superoutbursts

4. Discussion
4.1. Existence of Stage B–C Transition
4.4. Minimum Superhump Period and 3:1 Resonance
4.5. Maximum Superhump Period and Disk Radius
4.6. Superhump Period at the Start of Stage B
4.7. Stage C Superhumps in Positive Pdot Systems
4.8. Stage A Superhumps
4.9. ER UMa Stars
4.10. Long-Period Systems
4.11. Superhumps in Black-Hole X-Ray Transients
4.12. ε - q Relation
4.13. ε - Porb Relation

5. Period Variation of Superhumps in WZ Sge-Type Dwarf Novae
5.2. Period Variation in WZ Sge-Type Dwarf Novae
5.3. Period Variation versus Outburst Type

6. Individual Objects

7. Conclusion