Summary
Kidder accompanies Farmer on an extended hike through the Haitian countryside to visit patients. They walk for miles—11 hours in a single day—so that Farmer can treat two families of patients. Ti Jean, the clinic's handyman in Cange, accompanies the two men and often offers specifically Haitian interpretations on the things they see. Farmer and Kidder talk about the patients Farmer is treating, but primarily about the larger context of Farmer's work and criticisms of it. Kidder summarizes the two primary criticisms of Farmer's practice as (1) how can he justify dedicating so much time to individual patients when his time would be better spent working on a large scale, and (2) since no one else will be able to do what he did, his organizations offer flawed models for future programs. Farmer answers that working with theoretical models often ignores individual patients, and that not treating these suffering individuals sends the message that they matter less. A third thread of conversation is woven in with Ti Jean's commentary, and Farmer and Kidder's discussion of Farmer's mission: an ongoing highly personal account of the whole trip—including Kidder's chest pains, exhaustion, and dehydration—as a kind of adventure.

Analysis
By focusing the book's final chapter on another trip with Farmer through the Haitian countryside to visit patients, much like the one he had shared in Chapter 4, Kidder brings Mountains Beyond Mountains full circle. In the process of doing so, he returns to many earlier themes, much as a composer of a great symphony might. In an earlier expedition to Haiti, visitors had brought fish for Farmer's pond; in this chapter, Kidder visits the pond. Early chapters had touched on local medical beliefs versus Western medicine, and on how magical worldviews and scientific worldviews intersect; Ti Jean's commentary in this chapter provides an opportunity to return to these discussions, and so on. Even Farmer's references to Lord of the Rings show the narrative coming full circle, and all elements of his life carrying forward as he continues his mission.

However, the overwhelming point of this final chapter is to drive home the meaning of the title of this section of the book: "O for the P," which in PIH shorthand means a preferential "option for the poor." In the end, a viable O for the P forbids Farmer, or anyone, from resolving the apparent contraction of running a large scale organization and still hiking through the wilderness to treat patients. To do just the fundraising reduces people to statistics and abstractions; to do just the latter leaves the poor without the funds they need. Together, the political and the immediate, the economic and the personal, fuse in Paul Farmer, and in PIH and all of its variations, to create a viable, if highly demanding, O for the P.