'On the Tendency of Varieties to Depart Indefinitely From the Original Type' is a short article on variation and evolutionary theory.

'Attempts at a Natural Arrangement of Birds' is an article on the best way to classify different varieties of birds.

This work by Alfred Russel Wallace was originally published in 1873 and it is now republished with a brand new introductory biography. 'The Doctrine of Natural Selection' is a short article on Wallace's most lasting contribution to evolutionary theory.

'On the Varieties of Man in the Malay Archipelago' is an article on the distinct characteristics of humans inhabiting the Malay Archipelago.

'On the Law Which Has Regulated the Introduction of New Species' is an article that details Wallace's ideas on the natural arrangement of species and their successive creation.

Written by a famed 19th-century scientist who laid the groundwork for much of modern biology, this influential work remains one of the great classics of natural history and travel. Detailing his eight-year exploration of the Malay Archipelago, Wallace offers observations of the native people of the island groupings, the abundant and strange animals and insects, and more.

'On the Tendency of Species to form Varieties' is a landmark article on Wallace's ideas of natural selection in relation to evolutionary theory.

This work by Alfred Russel Wallace was originally published in 1908 and it is now republished with a brand new introductory biography. 'Evolution and Character' is an essay on explaining the key concepts and historical state of evolutionary theory.

'Monkeys' is an article that appeared in Popular Science Monthly and details the characteristics and geographical distribution of many species of monkey.

'Darwinism Applied to Man' contains an account of of the general identity of human and animal structure, diseases common to man and other animals, summary of the animal characteristics of man, and other aspects of evolutionary theory.