Krakauer uses many rhetorical devices to add credibility to his argument. This includes embedding quotes into his writing to allow the words of other people to strengthen his point. The following passage is a good example of how Krakauer utilizes these "quote sandwiches" throughout
Into Thin Air.
And now Pete Schoening was being led up Everest by Fischer and his two guides, Neal Beidleman and Anatoli Boukreev. When I asked Beidleman, a powerful climber from Colorado, how it felt to be guiding a client of Schoening's stature, he quickly corrected me with a self-deprecating laugh: "Somebody like me doesn't 'guide' Pete Schoening anywhere. I just consider it a great honor to be on the same team as him." Schoening had signed on with Fischer's Mountain Madness group not because he needed a guide to lead him up the peak but to avoid the mammoth hassle of arranging for a permit, oxygen, tentage, provisions, Sherpa support, and other logistical details. (p.92)
There are three parts of a quote sandwich, with the actual quote itself being the figurative "meat". The two pieces of anecdote precluding and after the quote make up the surrounding "bread" of the sandwich. By enclosing a quote inside the actual passage, Krakauer can build up an effective argument for himself.
The first two sentences set the stage for the point Krakauer is trying to make. Pete Schoening is part of an expedition with a set of very experienced climbers, including Scott Fischer, who we already know to be a professional climber. Neal Beidleman is revealed to be the guide for this team, a position reserved for those who have extensive knowledge on mountain climbing. By association, we can venture to guess that anyone on this team already has had years of mountain climbing experience.
The actual quote that follows the introductory sentences injects the passage with what Krakauer wants the reader to feel. The quote from Beidleman shows us that even the guides on this expedition feel inferior to Schoening's climbing ability. A direct quote from another source-who has considerable expertise on the subject, gives Krakauer's argument a great deal of strength.
To conclude the paragraph, Krakauer interjects with his final point on the subject. Schoening is not with this team because he needs the assistance in climbing Everest, he is there because he simply wants to avoid the other logistical problems that comes with going without a group. We as readers of the passage, know clearly what Krakauer is trying to tell us, and likely believe him.