After Gurney Halleck's harsh training session, Paul rests in the training room until Dr. Wellington Yueh arrives. Yueh tells Paul that regular lessons are canceled because Duke Leto will arrive soon, but Yueh has arranged study materials for the crossing to Arrakis.

Yueh discusses Arrakis with Paul, describing terranic life forms, the need to consult planetary ecologist Dr. Kynes, and the divided human population of Fremen and the people of the graben, sink, and pan. Paul is especially interested in the Fremen, whose blue-within-blue eyes come from melange saturation, and Yueh describes them as fierce, dangerous desert people whom Paul likely will not be allowed to mingle with.

Paul asks about sandworms, and Yueh explains that even a small specimen can be over one hundred meters long, with far larger worms reliably reported. Paul studies a chart and asks why the desert belt and south polar regions are marked uninhabitable; Yueh identifies worms and storms as the main dangers, stressing that Arrakis has costly perils.

Before leaving, Yueh gives Paul a miniature Orange Catholic Bible, an old printed book made for space travelers. Yueh frames the gift as a private secret, partly to soothe his conscience before betraying the Atreides and partly because the book carries personal meaning from his dead wife, Wanna.

When Paul opens the book, his unusually sensitive fingers find a notch marking Wanna's favorite passage rather than the one Yueh intended. Paul reads aloud about human deafness to unseen worlds, and Yueh abruptly stops him, shaken by grief. Paul senses that something mysterious has stirred in connection with his own terrible purpose, keeps the book, and formally thanks Yueh, while Yueh privately agonizes over the betrayal forced by the Harkonnens' hold over Wanna.