This article investigates the construction of the argumentative essay as it is commonly presented in academic writing textbooks and classrooms for English language learners. The author first examines the traditional three-stage structure (thesis-argument-conclusion) and then problematizes it within a genre-based approach to academic writing. He then describes and discusses authentic samples of argumentative writing using a moves analysis of 50 argumentative opinion blog entries, focusing on the organization of the stages as well as the positioning and articulation of the evaluation move (often referred to as the thesis statement). The authentic texts are then juxtaposed with argumentative essays in academic writing textbooks. The essential finding is that authentic argumentative writing varies considerably and thus presents a challenge to the commonly taught three-stage model.