Amazon.com description: Product Description: The most important and controversial biological book ever written, On The Origin of Species is Charles Darwin's foundation of evolutionary biology. The book, published in 1859, introduces Darwin's scientific theory: that populations evolve over the course of generations through a process of natural selection. Darwin included evidence gathered on the Beagle expedition in the 1830s in addition to research, correspondence, and experimentation. His findings were hotly debated by theological experts as well as scientists. While the journal is scientific, it is written in a simple style for non-specialist readers to enjoy and contemplate.