The objectives of the present paper are, first, to sketch the broad outlines of how writing skill develops across three stages, as a child matures and learns the craft of composition through late adolescence and into early adulthood. The first two - knowledge-telling and knowledge-transforming - are well documented. A third stage - knowledge crafting - is more speculative, but important for understanding expert or professional levels of writing skill. Second, it is suggested that the primary constraint on progression through these stages is the limited capacity of the central executive of working memory. Executive attention.
