This study was designed to enhance our understanding of the changing relationship between low- and high-level writing processes in the course of development. A dual description of writing processes was undertaken, based on (a) the respective time courses of these processes, as assessed by an analysis of eye and pen movements, and (b) the semantic characteristics of the writers' scripts. To conduct a more fine-grained description of processing strategies, a "case study" approach was adopted, whereby a comprehensive range of measures was used to assess processes within five writers with different levels of expertise. The task was to continue writing a story based on excerpt from a source document (incipit). The main results showed two developmental patterns linked to expertise: (a) a gradual acceleration in low- and high-level processing (pauses, flow), associated with (b) changes in the way the previous text was (re)read. (Contains 3 footnotes, 6 tables, and 6 figures.)