The article explores why Coase sometimes downplays and other times highlights his famous 'Coase theorem', named after him. It uncovers three main reasons for his mixed signals: first, the theorem helps to underline the importance of transaction costs; second, it criticizes a traditional viewpoint; and third, it offers suggestions for policy-making. Coase values the theorem, but also points out its limitations and uses it to challenge existing beliefs and shape policy recommendations.