Few issues in psychology are as fundamental or as elusive as the sense of one’s own body. Despite widespread recognition of the link between body and self, psychology has only recently developed methods for the scientific study of bodily awareness. Experimental manipulations of embodiment in healthy volunteers have allowed for important advances in knowledge. Synchronous multisensory inputs from different modalities play a fundamental role in producing body ownership: the feeling that my body is “mine.” Indeed, appropriate multisensory stimulation can induce a sense of ownership over external objects, virtual avatars, and even other people’s bodies. We argue that bodily experience is not monolithic, but rather has measurable internal structure and components that can be identified psychometrically and psychophysically, which suggests that the apparent phenomenal unity of self-consciousness may be illusory. We further review evidence that the sense of one’s own body is highly plastic, with representations of body structure and size particularly sensitive to multisensory influences.