I propose to write a book taking a comprehensive evolutionary, anthropological, developmental, and psychobiological approach to religious faith and practice as an evolved part of human nature. It will include rudiments of awe, ritual, and self-sacrifice in non-human species, elementary forms of religious life in the ethnographic record, the instantiation of faith in the naturally functioning human mind and brain, the development of empathy, moral awareness, and faith in childhood and adolescence, and the search for and sense of purpose in life that is of the essence of human adaptation. I will draw on my experience as an apprentice in the trance-dance religion of the Bushmen of Botswana, on my Orthodox Jewish childhood and adolescence, on my personal loss of faith, and on my indirect experience of other religious traditions to provide examples and illumination. I will also draw on the science and scholarship that have gone into my multidisciplinary books such as "The Tangled Wing: Biological Constraints on the Human Spirit" and "The Evolution of Childhood: Relationships, Emotion, Mind," as well as my books on the anthropology of the Jews. The book will address audiences in several academic disciplines and intelligent general readers both believing and non-believing. It will also serve as a rebuttal, from a scientific perspective, of certain attacks on religion mounted by scientists, philosophers, and essayists in recent years. I believe these attacks to be largely ignorant of religion as subjective experience and of the anthropological and biological foundations of religion in an objective sense. The goal of my project and my book is to redirect the conversation about the origins, nature, and role of religion in novel, integrative, and positive ways, and to explain why faith, despite not being universal to all individual human beings, is and always has been a part of every culture, and will always remain a part of human experience.