This document discusses research on writing in English for Specific Purposes (ESP). It covers three main approaches to ESP writing research: textual studies which examine how texts serve communicative purposes, contextual studies which consider the social contexts around text production, and critical studies which analyze how language constructs knowledge and power relations. Key findings include that written genres have culturally specific rhetorical structures and that there is often a disconnect between authentic professional writing and textbook representations. The future of ESP writing research may include new genres, deeper understanding of literacy contexts, and incorporating multimodality.