In the summer of 2019, a group of kia'i, or protectors made up of kanaka 'oiwi (Native Hawaiians) and their allies came together to demonstrate against the proposed construction of the Thirty-Meter Telescope (TMT) on the inactive volcano Maunakea. In Mele on the Mauna, Joseph Keola Donaghy explores how music, and especially haku mele, or Hawaiian language composers, played a crucial role in this defense. Musicians flocked to the mauna (mountain) to perform for the kia'i and a worldwide audience via social media. Haku mele created new songs at unprecedented levels, releasing many commercially with proceeds benefiting organizations providing support services and supplies to the kia'i. This book features over 30 of the author's interviews with individuals who participated in musical activities connected with this movement as well as recorded interviews conducted with kia'i, their supporters, officials from the state and university, and representatives from the TMT organization. Donaghy explores Indigenous Hawaiian concepts and theories like mana (power), mo'oku'auhau and pilina (genealogy and relationships), kapu aloha (discipline), and aloha 'aina (love of land, patriotism), and western academic concepts like connectedness and community building, poetics, sound(ing) and silenc(e/ing), conflict, and creativity. Mele on the Mauna illuminates how music played a powerful role in building solidarity, inspiration, and activism, reveling in the most contentious confrontations about protecting Maunakea and the outpouring of musical performances and creativity that occurred.