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

Arrakis—Dune—Desert Planet .
Paul sensed his own tensions, decided to practice one of the mind-body lessons his mother had taught him. Three quick breaths triggered the responses: he fell into the floating awareness . . . focusing the consciousness . . . aortal dilation . . . avoiding the unfocused mechanism of consciousness . . . to be conscious by choice . . . blood enriched and swift-flooding the overload regions . . . one does not obtain food-safety-freedom by instinct alone . . . animal consciousness does not extend beyond the given moment nor into the idea that its victims may become extinct . . . the animal destroys and does not produce . . . animal pleasures remain close to sensation levels and avoid the perceptual . . . the human requires a background grid through which to see his universe . . . focused consciousness by choice, this forms your grid . . . bodily integrity follows nerve-blood flow according to the deepest awareness of cell needs . . . all things/cells/beings are impermanent . . . strive for flow-permanence within . . .
Over and over and over within Paul's floating awareness the lesson rolled.
When dawn touched Paul's window sill with yellow light, he sensed it through closed eyelids, opened them, hearing then the renewed bustle and hurry in the castle, seeing the familiar patterned beams of his bedroom ceiling.
The hall door opened and his mother peered in, hair like shaded bronze held with a black ribbon at the crown, her oval face emotionless and green eyes staring solemnly.
"You're awake," she said. "Did you sleep well?"
"Yes."
He studied the tallness of her, saw the hint of tension in her shoulders as she chose clothing for him from the closet racks. Another might have missed the tension, but she had trained him in the Bene Gesserit Way —in the minutiae of observation. She turned, holding a semiformal jacket for him. It carried the red Atreides hawk crest above the breast pocket.
"Hurry and dress," she said. "Reverend Mother is waiting."
"I dreamed of her once," Paul said. "Who is she?"
"She was my teacher at the Bene Gesserit school. Now, she's the Emperor's Truthsayer. And Paul . . . " She hesitated. "You must tell her about your dreams."
"I will. Is she the reason we got Arrakis?"
"We did not get Arrakis." Jessica flicked dust from a pair of trousers, hung them with the jacket on the dressing stand beside his bed. "Don't keep Reverend Mother waiting."
Paul sat up, hugged his knees. "What's a gom jabbar?"
Again, the training she had given him exposed her almost invisible hesitation, a nervous betrayal he felt as fear.
Jessica crossed to the window, flung wide the draperies, stared across the river orchards toward Mount Syubi . "You'll learn about . . . the gom jabbar soon enough," she said.
He heard the fear in her voice and wondered at it.
Jessica spoke without turning. "Reverend Mother is waiting in my morning room. Please hurry."
The Reverend Mother Gaius Helen Mohiam sat in a tapestried chair watching mother and son approach. Windows on each side of her overlooked the curving southern bend of the river and the green farmlands of the Atreides family holding, but the Reverend Mother ignored the view. She was feeling her age this morning, more than a little petulant. She blamed it on space travel and association with that abominable Spacing Guild and its secretive ways. But here was a mission that required personal attention from a Bene Gesserit-with-the-Sight. Even the Padishah Emperor's Truthsayer couldn't evade that responsibility when the duty call came.
Damn that Jessica! the Reverend Mother thought. If only she'd borne us a girl as she was ordered to do!
Jessica stopped three paces from the chair, dropped a small curtsy, a gentle flick of left hand along the line of her skirt. Paul gave the short bow his dancing master had taught—the one used "when in doubt of another's station."
The nuances of Paul's greeting were not lost on the Reverend Mother. She said: "He's a cautious one, Jessica."
Jessica's hand went to Paul's shoulder, tightened there. For a heartbeat, fear pulsed through her palm. Then she had herself under control. "Thus he has been taught, Your Reverence."