This paper studies the composing strategies employed by four advanced L2 writers when they wrote in an academic setting and the rhetorical context of composing, i.e. their mental representations of the intended audience and of the rhetorical purpose for writing. Four student-teachers majoring in English and attending a postgraduate teacher education programme wrote an assignment in separate writing sessions that were videotaped. The writers were asked to think aloud, i.e. verbalize all the thoughts that went through their minds when they wrote. The think-aloud protocols were transcribed, coded and analyzed in conjunction with the plans and drafts that were produced in the writing sessions. In the follow-up interviews, the writers were asked questions on their mental representations of the intended audience and of the rhetorical purpose for writing. The findings suggested that the writers' mental representations of the intended audience and of the rhetorical purpose for performing the writing task appeared to have a correspondence with the ways that composing strategies were employed. In the process of composing, the writers made use of a broad range of strategies: cognitive, metacognitive and affective. Although they seemed to use a largely similar range of composing strategies, there was a significant difference in the extent to which different writers made use of these strategies. Different writers also used the same or similar strategies to serve different purposes at different junctures of the composing process. (Contains 8 tables.)