"On the Origin of Species By Means of Natural Selection" by Charles Darwin is a work of scientific literature published in 1859. It introduced the theory that populations evolve through natural selection, with life's diversity arising from common descent through a branching pattern of evolution. Darwin presented evidence from his Beagle expedition and years of research to challenge the belief that species were unchanging. The book sparked intense scientific, philosophical, and religious debate, ultimately transforming our understanding of life and becoming the foundation of evolutionary biology.
Project Gutenberg has several editions of this eBook: #1228 (1859, 1st Edition, HTML file with table of contents) #22764 (1860, HTML file with table of contents) #2009 (6th Ed., HTML, definitive edition) Wikipedia page about this book: en.wikipedia.org/wiki/On_the_Origin_of_Species See also PG#2009 for the 6th Edition