Increasingly, legal research projects undertaken at law school or in practice will involve Māori custom law and/or tikanga Māori.' The role of both Māori custom law and tikanga Māori is most evident in the work of the Māori Land Court in the interpretation and application of legislation relating to Māori land. Increasingly, general statutes incorporate Māori principles and values, such as those to be found in the Resource Management Act 1991, or make explicit reference to the principles of the Treaty of Waitangi. The statutory interpretation function of the Courts in relation to these, and less obvious examples, requires knowledge of tikanga Māori and/or Māori custom law. For any analysis of the work of the Courts or of the legislature, knowledge of tikanga Māori and/or custom law is required. Both Māori custom law and tikanga Māori are preserved by and accessed through the oral tradition. In addition to its role in the Courts and in relation to legislation, the most significant role played by the oral tradition is in the work of the Waitangi Tribunal. The oral tradition also plays an increasingly important part in other areas requiring research. What follows is an introduction to the oral tradition and its role in the legal system of Aotearoa/New Zealand. An understanding of the oral tradition is essential to the construction of a research path that is both ethical and effective.