1. A method of generating an e-book document, comprising the steps of: representing some or all of a page of an electronic document as a sequence of two or more graphic textures derived from the page of the electronic document, wherein the sequence comprises successively smaller graphic textures; arranging the graphic textures so generated to form a first mip-map suitable for use by 3D graphics hardware; generating, by a processor, a further mip-map of graphic textures corresponding to a layer of text, the graphic textures of the further mip-map being suitable for superposition over the graphic textures of the first mip-map during display by an e-book reader; and outputting, by the processor, an e-book document comprising said mip-maps.