"Charles Darwin's monumental work On the Origin of Species, first published in 1859, introduced the concept of natural selection, in which plant and animal species evolve over the course of generations according to their environmental conditions. Hotly debated and controversial when it was first proposed, Darwin's theory of evolution has become accepted as scientific fact today. This volume presents the text of the sixth edition of Darwin's work, with revisions that the author made over the course of more than a decade after the original publication"--
