In recent years there has been a revival of interest in traditional Māori musical instruments, including the kōauau. This thesis studies kōauau informed by a Māori framework, giving weight to traditional Māori knowledge and practices, emphasizing the spiritual dimensions of the instrument in its origins and its functions. The thesis defines the kōauau and how it is distinct from other taonga pūoro in its physical characteristics. It then presents the traditions associated with the kōauau which link its origins to the atua and their natural world, especially Raukatauri, together with other traditions from many rohe throughout Aotearoa. The thesis describes the traditional tools and methods of construction, the role of atua in the construction process, materials used for kōauau, how they were embellished, and their use as adornments. The techniques for playing kōauau are analyzed, and there is a discussion of the occasions on which kōauau were played, and the purposes of performing on kōauau. The thesis also presents the texts of several traditional waiata kōauau. A number of traditional kōauau in storage at the Auckland Museum were able to be examined to confirm and extend documentary evidence about materials, construction methods, and embellishment. The discussion also comments on the quot;voicesquot; for those kōauau in the museum collection that could be sounded. The decline in kōauau performance during the twentieth century is outlined, and there is a summary of successful efforts in the later twentieth century to revive taonga pūoro, including kōauau. The thesis brings together in concise form much scattered information so that current and future performers with kōauau are able to give full consideration to its place in te ao Māori.