The Missionaries was intended to be the concluding book of an autobiographical trilogy (beginning with Voices of the Old Sea and Jackdaw Cake) but instead was transmuted into a deeply searing examination of the extermination of indigenous tribes by North American fundamentalist missionaries. Lewis manages to maintain a magnificently superior calm as he gradually reveals, through their own words and actions, the self-serving illogicality, ruthless double-standards, and mercenary greed of the American missionaries. Fortunately Lewis's writing set off repercussions in his own lifetime, and Survival International was formed.