Combining elements appropriately within a coherent page layout is a well-recognized and crucial aspect of sophisticated information presentation. The precise function and nature of layout has not, however, been sufficiently addressed within computational approaches; attention is often restricted to relatively local issues of typography and text-formatting, leaving broader issues of layout unaddressed. In this paper we focus on the selection and function of layout in pages that appropriately combine textual and graphical representation styles to yield coherent presentation designs. We demonstrate that layout offers a rich resource for achieving presentational coherence, alongside more traditional resources such as text-formatting and the text-internal marking of discourse connections. We also introduce an integrated approach to layout, text, and diagram generation. Our approach is developed on the basis of a preliminary empirical investigation of professionally produced layouts, followed by implementation within a prototype information system in the area of art history.