In The Origin of Species Darwin outlined his theory of evolution, which proposed that species had been evolving and differentiating over time under the influence of natural selection. On its publication it became hugely influential, bringing about a seismic shift in the scientific view of humanity's place in the world that is still controversial today. It is both a brilliant work of science and also a clear, vivid and at times even moving, piece of writing that reflects both Darwin's genius and his boundless enthusiasm for the natural world. With an Afterword by Oliver Francis