This booklet is part of a series published by the Northwest Regional Educational Laboratory on "hot topics" in the field of education. The topic is Writing Across the Curriculum (WAC). There is growing concern about the writing curriculum and instruction among educators, researchers, and policymakers, especially at the middle and high school levels. These concerns result from poor performance by many students on statewide writing assessments. As teachers are faced with limited time, they are looking for ways to incorporate writing into the content areas. Many are finding this practice to be not only a valuable way to save teaching time, but also an important tool for reflection and making connections with material in the content areas. This piece provides a brief overview of theories and research, explains common strategies for WAC, and describes ways to implement WAC into the middle and high school levels. (authors/aec)