In 1930 a young Dutch scholar named W.F. Wertheim published his J.D.-dissertation Aansprakelijkheid voor schade buiten overeenkomst (Extra-contractual liability for damage). This dissertation did not attract much attention, and the author himself hardly did any further research on its topic. Taking in mind the development of law-and-economics some decades later, however, the book is highly remarkable. Long before the modern economic analysis of law was to be developed in the United States, attention was paid to the preventive effects of liability law and its influence on the welfare of society. In the first paragraph of this paper, Wertheims theory will be explained. The second paragraph is devoted to the reception of the book by the legal community and to the second thoughts the author himself had about it. In the third paragraph a comparison is made between method and application of Wertheim’s theory and contemporary law-and-economics. The fourth paragraph offers a conclusion.