This is a speculative essay in comparative possibilities. It looks at some widely separated religious contexts in which a power-laden relationship across ontological difference – for instance, between living humans and a world of gods or spirits – is mediated by operations on the materiality of the written sign. These operations typically result in either materializing something immaterial or dematerializing something material. But they may also involve other activities that take advantage of specific physical properties of the written word such as being persistent, transportable, perishable, alienable, and so forth. Once divine words are rendered into script, they possess a distinctively material quality and form. They appear on some physical medium, and so are both durable and potentially destructible. Anything that can happen to another artefact can happen to them. The practices I dub ‘spirit writing’ subject the written word to radical transformation, taking advantage of its very materiality in order to dematerialize it, even if only in order to be rematerialized in yet some other form (such as a person's body). Many such practices seek to generate or control religious powers by means of transduction across semiotic modalities, material activities that help render experience-transcending forces realistic or at least readily imaginable.