This case note analyses the High Court's recent landmark decision in D'Arcy v Myriad Genetics Inc [2015] HCA 35. In three separate judgments ultimately united on the result, the High Court held that patent claims to isolated human DNA used in testing for breast cancer were not a 'manner of manufacture' within the meaning of s 6 of the Statute of Monopolies. The claims were therefore not patent-eligible subject matter in Australia. It is submitted that the plurality's new factorial approach to patentability for new classes of claims rearticulates the approach propounded in the High Court's seminal decision in NRDC. D'Arcy's new guiding factors therefore rea1ign the subject matter inquiry with its true nature, which turns on, in the plurality's words, the 'historically contingent concepts of patent and invention'. The note concludes by examining three of the most pressing consequences of D'Arcy's reasoning for Australian patent law.