In the book, Darwin presents the evidence he had collected from his observations and research, which led him to propose his theory of evolution by natural selection. This theory posits that species evolve over time through the process of natural selection, in which individuals with certain advantageous traits are more likely to survive and pass on those traits to their offspring."The Origin of Species" was controversial at the time of its publication and sparked considerable debate among scientists and the public. It challenged the prevailing view of creationism and caused some to question the role of God in the natural world.