In Ka Poe Kahiko, Kamakau documents fundamental principles underlying the daily activities of Hawaiian life. He focuses on the spiritual and religious aspects of Hawaiian society, including a description of its class structure. The closing chapters discuss traditional medical practices, and briefly explore magic and sorcery. A devout Christian, Kamakau approaches old beliefs with a complex mixture of traditional and Christian thought.

The text is translated and edited from a series of articles Kamakau produced for the Hawaiian-langauge newspapers Ku‘oko‘a and Ke Au ‘Oko‘a between 1866 and 1871. Subsequent volumes in this series include The Works of the People of Old: Na Hana a ka Poe Kahiko and Tales and Traditions of the People of Old: Na Moolelo a ka Poe Kahiko also published by Bishop Museum Press.