22. The process of claim 21 further comprising the step of storing the text content of the digital document separate from the digital document and without descriptive markup, and wherein the indication of the text content contained within an element stored in the element descriptor of the element is indicative of the location of the text content contained within the element in the separately stored text content.
21. A process for constructing a digital information product comprising computer data signals defining a representation of a digital document, the digital document having descriptive markup defining a plurality of hierarchical elements, wherein each element except a root element has an ancestor element and wherein each element has a type name and may have a child element, a left sibling element and a right sibling element, and wherein at least one element contains text content, the process comprising: parsing the digital document to provide a sequence of element events in response to detection of elements and text events in response to detection of text content; assigning a unique element identifier to each element; constructing the type name for each element from the descriptive markup defining the element; and constructing, for each element, an element descriptor addressable by the element identifier assigned to the element, wherein the element descriptor stores an indication of the type name and any parent element, first child element, last child element, left sibling element, right sibling element, and text content contained within the element, and encoding each element descriptor in a computer data signal.