Thiong'o authored The River Between in 1965. Like most of his writings, this novel deals with the clash between the native people of Kenya and the struggles of colonialism. Commitment to one's culture and community is a common theme in most of this author's work.
The main theme throughout is the loss of culture due to outside forces and invasion as Christian missionaries attempt to impose a new way of life on indigenous tribes. The rights of the indigenous culture to maintain a way of life socially, religiously, educationally and economically when invaded by others who attempt to impose a new way of life on them is dealt with throughout the novel.
Another theme that coincides with the commitment to culture and possible loss of that culture by force is that of action. In the novel, the main character Waiyaki realizes that to maintain the culture even as it is changing due to colonial influences, the people must take action to preserve and protect it.
One of the themes is the conflict caused by imperialism and the clash of tribal and Christian cultures.
As more and more countries began carving out pieces of Africa for themselves, the conflict of cultures became greater. The book describes the effect of the attempts to spread Christianity, the impact of White culture on the Africans, and the conflicting values of the traditional ways with modern ones.
Chege tells his son Waiyaki that he must go to learn the ways of the white man, but tells him, “do not follow their vices” (p. 20). He feels that the white man is not going to go away, and they need to know his strengths.
When the white man came and fixed himself in Siriana, I warned all the people. But they laughed at me. Maybe I was hasty. (p. 20)
The clash of cultures affects different characters certain ways, but the botched circumcisions show that the old ways come into conflict with the new. The people are seeing the threat to their way of life, because the younger ones do not appreciate the old methods and traditions.