Here is the footage of the Prize Lecture Oliver Hart delivered on 8 December 2016 at Stockholm University.
The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel (aka Nobel Prize in Economics) was awarded this year jointly to Oliver Hart and Bengt Holmström "for their contributions to contract theory." Contract theory is a branch of economics that studies optimal design of contractual arrangements as well as offers explanation for the contracts as they are commonly written. It's highly relevant to Law & Economics (some would even classify it within the field) and provides great insights for both contract law and legal practice. A concise summary of their contribution to the field can be found here.