Second appearance of this seminal group of three papers, reprinted from the Journal of the Proceedings of the Linnean Society (Vol. III, No. 9, also 1858). The papers, which predate by a year the publication of Darwin's On the Origin of Species, are: "Extract from an unpublished work on Species by C. Darwin, Esq., consisting of a portion of a Chapter intituled, `On the Variation of Organic Beings in a state of Nature; on the Natural Means of Selection; on the Comparison of Domestic Races and true Species,'"; "Abstract of a Letter from C. Darwin, Esq., to Prof. Asa Gray, Boston, U.S., dated Down, September 5th, 1857"; and "On the Tendency of Varieties to depart indefinitely from the Original Type" by Alfred Russell Wallace.