This chapter describes the enormous amount of scientific evidence that has accumulated since the publication of Darwin’s books and complements Darwin’s original assertions that evolution occurs through incremental changes in characteristics and diversification of form through natural selection. First, with the rediscovery of Mendel’s theory of particulate inheritance, genetics had to be incorporated into evolutionary thought. After much debate, the modern synthesis of genetics, population genetics, and natural selection became the predominant theory of evolution. It did not refute Darwin; it added to Darwin’s theory. Further, paleontology has documented a historical record of life on Earth that corroborates the view that organisms gradually and sometimes more quickly changed over time. Third, the field of molecular genetics has established the genetic relationships shared by all living organisms and has been able to reconstruct timelines of multiple lineages of organisms, including humans. Finally, evolution has been observed in real-time in numerous scenarios. The evolution of antibiotic resistance and Galapagos finches are just two examples.