“One of the most memorably unexpected events I experienced in the course of doing this book came in a dissection room at the University of Nottingham in England when a professor and surgeon named Ben Ollivere (about whom much more in due course) gently incised and peeled back a sliver of skin about a millimeter thick from the arm of a cadaver. It was so thin as to be translucent. “That,” he said, “is where all your skin color is. That’s all that race is—a sliver of epidermis.” I mentioned this to Nina Jablonski when we met in her office in State College, Pennsylvania, soon afterward. She gave a nod of vigorous assent. “It is extraordinary how such a small facet of our composition is given so much importance,” she said. “People act as if skin color is a determinant of character when all it is is a reaction to sunlight. Biologically, there is actually no such thing as race—nothing in terms of skin color, facial features, hair type, bone structure, or anything else that is a defining quality among peoples. And yet look how many people have been enslaved or hated or lynched or deprived of fundamental rights through history because of the color of their skin.”