The article examines how textbooks teach Coase's ideas on fixing negative external effects. Most textbooks link Coase's ideas to Stigler's Coase Theorem, but Coase's original work has a different approach. By studying old writings, the authors show that there are two main ways to deal with negative effects: one following Pigou, Stigler, and Samuelson, and the other following Coase. They looked at 45 economics books and found that many don't present Coase's views accurately. A Coasean approach challenges students to think critically rather than just promoting minimal interference or intervention.