In the interest of finding ways to help their students succeed in university studies, college‐level L2 writing researchers and teachers have endeavored for years to define the nature of academic writing tasks. The effort to determine what academic writing is and what ESL students need to know in order to produce it has led to the development of a number of different approaches to the teaching of writing. Most recently, this effort has led to a problematic trend toward having teachers of English, including teachers of freshman composition, teach students to write in other disciplines. This trend has emerged in response to criticism of previous writing programs, analyses of surveys of academic writing tasks, and movements such as Writing Across the Curriculum and English for specific purposes. This article reviews studies of L1 writing programs in which students learn to write in various disciplines, discusses the implications of the researchers' findings, and argues that (a) the teaching of writing in the disciplines should be left to the teachers of those disciplines and (b) L2 English composition teachers should focus on general principles of inquiry and rhetoric, with emphasis on writing from source