Recent considerations of threshold concepts in the rhetoric and writing studies discipline fail to consider the role that reading plays in the learning of student writers. This article reports results from a three-part, two-year, empirical study of seventy-five learners enrolled across four sections of a writing-intensive course. The course focused on disciplinary writing, and the study used observations, surveys, and interviews to examine the relationships among the course, the learners enrolled in it, and the reading associated with it. Data was gathered at two points during the course, as well as one year following the course, and results indicate that the reading that occurs in a writing-intensive course is transformative across the disciplines.