Among the central themes of Bruchko is the complexities of cross-cultural missionary work. Missionary work aims to bridge gaps across cultures through spreading Christianity, but this endeavor brings considerable challenges. Throughout Bruchko, Olson is keen to highlight these challenges and demonstrate how his approach to overcoming them is effective.

Olson’s mission in South America faces numerous challenges because of cultural differences. First, linguistically, Olson struggles to communicate with those he hopes to convert; he does not speak Spanish when he arrives in Venezuela, and for both the Yuko and the Barí, Olson must learn entirely unfamiliar languages. Second, by inserting himself into a region with a history of violence between Indigenous and settler communities, Olson has to overcome preexisting mistrust. His harsh reception by the Yuko is caused by the recent murder of two Yukos by outsiders, and the Barí are prone to violence against outsiders because of the frequent attempts to exploit their land. Finally, issues arise from the differences in cultural values between Olson and the Indigenous tribes. The Barí’s traditions of non-individualism and hiding negative emotions are starkly different from Olson’s experience of North American life, causing issues in how he can relate a message to people without the life experience he is used to.