From "Manual of Muad'Dib" by the Princess Irulan

She thinks I worry for her! He blinked back tears. And I do, of course. But I must stand before that black Baron with his deed accomplished, and take my one chance to strike him where he is weakest—in his gloating moment!
He sighed.
"Would it disturb Paul if I looked in on him?" she asked.
"Not at all. I gave him a sedative."
"He's taking the change well?" she asked.
"Except for getting a bit overtired. He's excited, but what fifteen-year-old wouldn't be under these circumstances?" He crossed to the door, opened it. "He's in here."
Jessica followed, peered into a shadowy room.
Paul lay on a narrow cot, one arm beneath a light cover, the other thrown back over his head. Slatted blinds at a window beside the bed wove a loom of shadows across face and blanket.
Jessica stared at her son, seeing the oval shape of face so like her own. But the hair was the Duke's—coal-colored and tousled. Long lashes concealed the lime-toned eyes. Jessica smiled, feeling her fears retreat. She was suddenly caught by the idea of genetic traces in her son's features—her lines in eyes and facial outline, but sharp touches of the father peering through that outline like maturity emerging from childhood.
She thought of the boy's features as an exquisite distillation out of random patterns—endless queues of happenstance meeting at this nexus. The thought made her want to kneel beside the bed and take her son in her arms, but she was inhibited by Yueh's presence. She stepped back, closed the door softly.
Yueh had returned to the window, unable to bear watching the way Jessica stared at her son. Why did Wanna never give me children? he asked himself. I know as a doctor there was no physical reason against it. Was there some Bene Gesserit reason? Was she, perhaps, instructed to serve a different purpose? What could it have been? She loved me, certainly .
For the first time, he was caught up in the thought that he might be part of a pattern more involuted and complicated than his mind could grasp.
Jessica stopped beside him, said: "What delicious abandon in the sleep of a child."
He spoke mechanically: "If only adults could relax like that."
"Yes."
"Where do we lose it?" he murmured.
She glanced at him, catching the odd tone, but her mind was still on Paul, thinking of the new rigors in his training here, thinking of the differences in his life now—so very different from the life they once had planned for him.
"We do, indeed, lose something," she said.
She glanced out to the right at a slope humped with a wind-troubled gray-green of bushes—dusty leaves and dry claw branches. The too-dark sky hung over the slope like a blot, and the milky light of the Arrakeen sun gave the scene a silver cast—light like the crysknife concealed in her bodice.
"The sky's so dark," she said.
"That's partly the lack of moisture," he said.
"Water!" she snapped. "Everywhere you turn here, you're involved with the lack of water!"
"It's the precious mystery of Arrakis," he said.
"Why is there so little of it? There's volcanic rock here. There're a dozen power sources I could name. There's polar ice. They say you can't drill in the desert—storms and sandtides destroy equipment faster than it can be installed, if the worms don't get you first. They've never found water traces there, anyway. But the mystery, Wellington , the real mystery is the wells that've been drilled up here in the sinks and basins. Have you read about those?"
"First a trickle, then nothing," he said.
"But, Wellington , that's the mystery. The water was there. It dries up. And never again is there water. Yet another hole nearby produces the same result: a trickle that stops. Has no one ever been curious about this?"
"It is curious," he said. "You suspect some living agency? Wouldn't that have shown in core samples?"
"What would have shown? Alien plant matter . . . or animal? Who could recognize it?" She turned back to the slope. "The water is stopped. Something plugs it. That's my suspicion."
"Perhaps the reason's known," he said. "The Harkonnens sealed off many sources of information about Arrakis. Perhaps there was reason to suppress this."
"What reason?" she asked. "And then there's the atmospheric moisture. Little enough of it, certainly, but there's some. It's the major source of water here, caught in windtraps and precipitators. Where does that come from?"
"The polar caps?"
"Cold air takes up little moisture, Wellington . There are things here behind the Harkonnen veil that bear close investigation, and not all of those things are directly involved with the spice."
"We are indeed behind the Harkonnen veil," he said. "Perhaps we'll . . ." He broke off, noting the sudden intense way she was looking at him. "Is something wrong?"
"The way you say 'Harkonnen,' " she said. "Even my Duke's voice doesn't carry that weight of venom when he uses the hated name. I didn't know you had personal reasons to hate them, Wellington ."