The aim of this paper is to explore the correlation between writing classes and textbooks on academic writing through the case study of ‘academic writing’ classes, the textbook titled Critical Thinking Academic Writing and student essays produced at Sungkyunkwan University. In particular, through the case study of Sungkyunkwan University, I confirmed how the textbook reflects the goals of writing classes and liberal arts education in general. I examined the textbook contents and composition in relation to the strategy of writing. And I empirically confirmed the effectiveness of the textbook through the analysis of student essays. In order to do this, I suggested the necessity of research on the effectiveness of writing textbooks and the correlation between writing classes and textbooks. Through this, we expect that students can enjoy the effects of writing education better through the improvement of the quality of textbook, a key tool for writing classes.