On the Origin of Species
On the Origin of Species is about Natural Selection and Survival of the Fittest
Chapter 1
Variation under Domestication →

Chapter 1b
The Influence of Habit →

Chapter 1c
Reverting to the Wild State →

Chapter 1d
The Breeds of the Domestic Pigeon →

Chapter 1e
Selection →

Chapter 1f
Unconscious Verus Methodical Selection →

Chapter 1g
Variation under Domestication →

Chapter 2
Variation Under Nature →

Chapter 2b
Species Versus Variety →

Chapter 2c
Incipient Species →

Chapter 2d
The Principle of Divergence of Character →

Chapter 3
Struggle for Existence →