The premise is that each photo in the book is a sexual photograph in this sense. This, of course, begs the question, "What is sex?" a question that each person will answer differently. Photo Sex collectively offers the author/photographer's personal perspective on what is included in the sexual realm--a perspective which is fairly broad.
A wide audience for photography views sex in a more complex, subtle, and interesting way than commercial pornography can offer. This broad audience includes women as well as men, and people of all ages, ethnicities, and sexual orientations who are interested in exploring sex in depth, rather than reducing its complexity and wonder to cliches.
Photo Sex is inclusive in its choice of both subjects and subject matter, with images of middle-aged and older people as well as youth, of heavy people as well as thin, of people who represent a broad range of genders, ethnicities, sexual tastes, and sexual orientations. The photos confirm that all sorts of "ordinary" people are both sexy and sexual.