"On the Origin of Species" is a groundbreaking book written by Charles Darwin in 1859. It introduces the theory of evolution through natural selection, explaining how species adapt and change over time. Darwin argues that those individuals best suited to their environment are more likely to survive and reproduce, passing on their traits to future generations. The book challenges traditional views of creation and provides evidence from various fields, including geology, paleontology, and biology. By presenting a wealth of observations and examples, Darwin lays the foundation for modern evolutionary biology, influencing how we understand the diversity of life on Earth.