In 1921 the U.S. Congress officially defined “Native Hawaiians” as those people “with at least one-half blood quantum of individuals inhabiting the Hawaiian Islands prior to 1778.” This “blood logic” has since become an entrenched part of the Hawaiian legal system, determining access to land claims and tax exemptions. Blood quantum has also had a profound effect on cultural definitions of indigeneity, transforming notions of kinship and belonging among Native Hawaiians (Kanaka Maoli). Hawaiian Blood is an impassioned assessment of the far-reaching legal and cultural effects of the arbitrary correlation of blood and race imposed by the U.S. government on the indigenous peoples of Hawai‘i. J. Kehaulani Kauanui demonstrates how blood quantum, a system originally intended to restore land to Native Hawaiians, has in fact undermined Kanaka Maoli sovereignty claims and become an extension of U.S. imperial power in Hawai‘i. Within the framework of the fifty-percent rule, intermarriage “dilutes” the number of state-recognized Native Hawaiians. Rather than supporting Native claims to the Hawaiian islands, blood quantum reduces Hawaiians to a racial minority, reinforcing a system of white racial privilege bound to property ownership. Moreover, as Kauanui explains, the exclusionary logic of blood quantum runs counter to inclusive Kanaka Maoli genealogical and kinship practices. In Hawaiian Blood Kauanui provides the first comprehensive history and analysis of how a federal law equating Hawaiian cultural identity with a quantifiable amount of blood was created. She emphasizes the ongoing significance of blood quantum: Its criteria underlie recent court decisions regarding Hawaiian entitlements and new proposals for Hawaiians to gain status akin to tribal nations. Those proposals are subverting the Hawaiian sovereignty movement and bringing to the fore charged questions about who counts as Hawaiian.