A method includes receiving a machine readable file containing a document that is to be served to a client for display on a client device, the organization of each of the documents in the file being expressed as a hierarchy of information, and deriving subdocuments from the hierarchy of the information, each of the subdocuments being expressed in a format that permits it to be served separately to the client using a hypertext transmission protocol, at least one of the subdocuments containing information that enables it to be linked to another one of the subdocuments.