We cannot talk of evolution without mentioning Darwin. Charles Darwin was a Unitarian. His theory on natural selection was incomplete 150 years ago, but today, many questions have been answered. The theory of evolution generated new scientific disciplines, such as the study of DNA, that further our understanding of life. No one who respects science denies the importance of Darwin's discoveries.
Books and Online Resources
On the Origin of Species: The Illustrated Edition by Charles Darwin (Sterling, 2008), released to honor the 150-year anniversary of the book's original publication
The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe without Design by Richard Dawkins (W. W. Norton & Co., 1996)
The Blank Slate: The Modern Denial of Human Nature by Steven Pinker (Penguin, 2003)
The Flamingo's Smile: Reflections in Natural History by Stephen Jay Gould (W. W. Norton & Co., 1987)
The Selfish Gene by Richard Dawkins (Oxford University Press, 2006)
The Third Chimpanzee: The Evolution and Future of the Human Animal by Jared Diamond (Harper Perennial, 2006)
Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body by Neil Shubin (Vintage, 2009).