No / We present a framework for the describing the genres of illustrated documents, based on analysis at five levels: content structure, rhetorical structure, layout structure, navigation structure, and linguistic structure. We also include three sources of constraints under which a document might be produced and interpreted: canvas constraints, production constraints, and consumption constraints. Document genres are conceptualised as complex specifications composed of descriptions at each of the five levels that conform in characteristic ways to the three kinds of constraint. We propose that the eight parameters together form a 'space' of possible identities for documents, electronic or paper. The notion of 'genre space' captures the fact that it is possible for new genres to develop at different positions in the space, as well enabling relationships between document types, or even transformations between them, to be examined and described.