The title evokes several themes of the work, which examines how a Christian account of sexuality appears alien to us, as it is a "heavenly" sexuality not natural to our fallen state. The book explores, for example, the ways in which sexuality has sometimes been construed as an alien force within the body, as in the writings of St. Augustine. It also addresses the ways in which certain contemporary cultural texts, such as David Fincher's film Alien(3), continue the Augustinian theme in a secular mode, construing sexuality as an alien threat to human life and evoking fears about AIDS and childbirth. The study's goal, to view sexuality from the perspective of heaven, is not intended to etherealize the body, but to focus readers on just how bodily and biological so much of Christian theology is.