This thesis argues that process-oriented approaches to second language writing instruction have been overly influenced by first language writing theory and that, in consequence, these pedagogies have paid too much notice to the difficulties encountered by unskilled writers. The thesis calls for the need for second language writing instruction to recognize the differences between skilled and unskilled writers and address the specific difficulties of the former. It is reasoned that skilled writers using L2 need far more support with regard to acquiring language-specific standards with which to evaluate their own prose than with regard to developing writing process planning, writing, rereading and revising skills (which they already possess). The empirical part of this study investigates the effects of a discourse-oriented programme of L2 writing instruction upon the ability of skilled writers to improve their written production. The pedagogy tested did not attempt to teach writing process strategies, but seeked to provide a group of eight Brazilian researchers writing in English with parameters with which to improve the readability of their writing products in the absence of teacher feedback. Pre and post-instruction samples of expository texts and revision data by these writers disclose evidence that the instruction carried out was effective and efficient: the writers were able to improve the readability of their writing products and acquire standards with which to evaluate their own prose in the absence of teacher feedback after a very short instructional period. Although it was not possible to work with a control group, a detailed analysis of the revision data suggests that the above developments are more likely to have been outcomes of the specific instruction provided than outcomes of any type of writing instruction. It was concluded that skilled writers using L2 may greatly benefit from instruction which focuses on how L2 discourse is organized, and that the teaching of writing process strategies need not be a priority when the learners in question are already skilled writers. A final concern of the study was to learn more about instruction for skilled writers using L2. Its most important exploration in this respect suggests that instruction must strive to help these writers overcome language-specific difficulties that emerge during the process of writing. These difficulties are not always visible in finished products, and may easily be mistaken for lack of writing skill.