Despite its sensational title, Bock's account of his travels in the 1870s in both Borneo and Sumatra covers much more than the well-known head-hunting pursuits of the Dayaks. Bock proved to be a keen observer not only of the way of life of the peoples of the interior but also of their titulary Malay overlords and of various aspects of colonial life. Bock's descriptions of his journeys in Sumatra, taken in this instance primarily as a naturalist, also portrays vividly scenes of contemporary life and society in an era of Dutch expansion along with observations of the flora and fauna.