Natural Selection: On the Law which has Regulated the Introduction of New Species; On the Tendency of Varieties to Depart Indefinitely from the Original Type; Mimicry, and other Protective Resemblances Among Animals; On Instinct in Man and Animals; the Philosophy of Birds' Nests; A Theory of Birds' Nests; Creation by Law; The Development of Human Races Under the Law of Natural Selection; The Limits of Natural Selection as Applied to Man.

Tropical Nature and Other Essays: The Climate and Physical Aspects of the Equatorial Zone; Equatorial Vegetation; Animal Life in the Tropical Forests; Hummingbirds: As Illustrating the Luxuriance of Tropical Nature; The Colors of Animals and Sexual Selection; The Colors of Plants and the Origin of the Color-Sense; The Antiquity and Origin of Man; The Antiquity of Man in North America; and The Debt of Science to Darwin.