A model can be an object of admiration, a miniature or prototype, an abstracted phenomenon or applied theory, a literary text — practically anything from a human body on a catwalk to a mathematical description of a system. It can elicit desire, provide understanding, guide action or thought. Despite the polysemy of the term, models across disciplines and fields share a fundamental characteristic: their effect depends on a specific relational quality. A model is always a model of or for something else, and the relation is reductive insofar as it is selective and considers only certain aspects of both object and model. The literary examples of maps made to the scale of a territory described by Lewis Carroll and Jorge Luis Borges humorously point to the absurdity of thinking that models keep improving by becoming less reductive until they eventually coincide with their target.