Hair is one of the most distinctive features of the human species and of individual people. It protects us, and is one of our most important instruments of nonverbal communication. Enormous amounts of time, effort, and technological expertise have been expended on hair over millennia, and “cultures of hair” perfuse modern life. People are obsessed with hair, but often don’t talk about it for fear of being seen as vain or superficial. Hair is serious business in every sense of the word, as attested by Hillary Clinton’s now famous quote, “Pay attention to your hair, because everyone else will.” The biology and evolutionary history of hair provide fascinating entry points into explorations of hair as a personal statement, a cultural expression, and a driver of technological change through human history. Hair is identity. Its color, texture, and style – or the very absence of it – speak not only to our biology and ancestry, but to our personalities, motivations, and aspirations. There is no part of the body that can be more dramatically modified in the course of normal life than the hair. During my period of Fellowship at STIAS in early 2020, I will work on writing a new new and comprehensive book on human hair, that begins with the basic questions of why we have hair in the places we do, why and how hair came to be a focus of the culture of human appearance, and how people use hair to express themselves in rituals of personal performance. Hair summarizes the human condition, and in this book will take center stage.