This single subject study concerns a 14 year-old academically gifted student's use of metacognition when producing written discourse in response to a writing prompt. Ethnographic procedures were used to collect and analyze data. The participant engaged in a think-aloud procedure as he composed an expository paper, and his transcribed verbalizations were then analyzed for metacognitive strategy use. The strategies were organized into a taxonomy by means of Spradley's domain and taxonomic analysis. Results indicated that the participant advanced the writing process by employing five major types or domains of strategies. They are: (a) planning discourse/thinking, (b) evaluating discourse/thinking, (c) recognizing difficulty with discourse/thinking, (d) responding to difficulty with discourse/thinking, and (e) repairing discourse/thinking. The participant employed over 80 individual strategies within these five domains as he wrote a well organized and cohesive composition at one of Britton et al.'s higher abstractive levels of discourse.