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

This was a penetrating question , the Baron thought. Have I misjudged this nephew?
"The Emperor doesn't know it yet," the Baron said. "But his Sardaukar are sure to report it to him. Before that happens, though, I'll have my own report in his hands through CHOAM Company channels. I will explain that I luckily discovered a doctor who pretended to the conditioning. A false doctor, you understand? Since everyone knows you cannot counter the conditioning of a Suk School , this will be accepted."
"Ah-h-h, I see," Rabban murmured.
And the Baron thought: Indeed, I hope you do see. I hope you do see how vital it is that this remain secret . The Baron suddenly wondered at himself. Why did I do that? Why did I boast to this fool nephew of mine—the nephew I must use and discard? The Baron felt anger at himself. He felt betrayed.
"It must be kept secret," Rabban said. "I understand."
The Baron sighed. "I give you different instructions about Arrakis this time, Nephew. When last you ruled this place, I held you in strong rein. This time, I have only one requirement."
"M'Lord?"
"Income."
"Income?"
"Have you any idea, Rabban, how much we spent to bring such military force to bear on the Atreides? Do you have even the first inkling of how much the Guild charges for military transport?"
"Expensive, eh?"
"Expensive!"
The Baron shot a fat arm toward Rabban. "If you squeeze Arrakis for every cent it can give us for sixty years, you'll just barely repay us!"
Rabban opened his mouth, closed it without speaking.
"Expensive," the Baron sneered. "The damnable Guild monopoly on space would've ruined us if I hadn't planned for this expense long ago. You should know, Rabban, that we bore the entire brunt of it. We even paid for transport of the Sardaukar."
And not for the first time, the Baron wondered if there ever would come a day when the Guild might be circumvented. They were insidious—bleeding off just enough to keep the host from objecting until they had you in their fist where they could force you to pay and pay and pay.
Always, the exorbitant demands rode upon military ventures. "Hazard rates," the oily Guild agents explained. And for every agent you managed to insert as a watchdog in the Guild Bank structure, they put two agents into your system.
Insufferable!
"Income then," Rabban said.
The Baron lowered his arm, made a fist. "You must squeeze."
"And I may do anything I wish as long as I squeeze?"
"Anything."
"The cannons you brought," Rabban said. "Could I—"
"I'm removing them," the Baron said.
"But you—"
"You won't need such toys. They were a special innovation and are now useless. We need the metal. They cannot go against a shield, Rabban. They were merely the unexpected. It was predictable that the Duke's men would retreat into cliff caves on this abominable planet. Our cannon merely sealed them in."
"The Fremen don't use shields."
"You may keep some lasguns if you wish."
"Yes, m 'Lord. And I have a free hand."
"As long as you squeeze."
Rabban's smile was gloating. "I understand perfectly, m'Lord."
"You understand nothing perfectly," the Baron growled. "Let us have that clear at the outset. What you do understand is how to carry out my orders. Has it occurred to you, nephew, that there are at least five million persons on this planet?"
"Does m'Lord forget that I was his regent-siridar here before? And if m'Lord will forgive me, his estimate may be low. It's difficult to count a population scattered among sinks and pans the way they are here. And when you consider the Fremen of—"
"The Fremen aren't worth considering!"
"Forgive me, m'Lord, but the Sardaukar believe otherwise."
The Baron hesitated, staring at his nephew. "You know something?"
"M'Lord had retired when I arrived last night. I . . . ah, took the liberty of contacting some of my lieutenants from . . . ah, before. They've been acting as guides to the Sardaukar. They report that a Fremen band ambushed a Sardaukar force somewhere southeast of here and wiped it out."
"Wiped out a Sardaukar force?"
"Yes, m'Lord."
"Impossible!"
Rabban shrugged.
"Fremen defeating Sardaukar," the Baron sneered.
"I repeat only what was reported to me," Rabban said. "It is said this Fremen force already had captured the Duke's redoubtable Thufir Hawat."
"Ah-h-h-h-h-h."
The Baron nodded, smiling.
"I believe the report," Rabban said. "You've no idea what a problem the Fremen were."
"Perhaps, but these weren't Fremen your lieutenants saw. They must've been Atreides men trained by Hawat and disguised as Fremen. It's the only possible answer."
Again, Rabban shrugged. "Well, the Sardaukar think they were Fremen. The Sardaukar already have launched a program to wipe out all Fremen."
"Good!"
"But—"
"It'll keep the Sardaukar occupied. And we'll soon have Hawat. I know it! I can feel it! Ah, this has been a day! The Sardaukar off hunting a few useless desert bands while we get the real prize!"
"M'Lord . . . " Rabban hesitated, frowning. "I've always felt that we underestimated the Fremen, both in numbers and in—"
"Ignore them, boy! They're rabble. It's the populous towns, cities, and villages that concern us. A great many people there, eh?"
"A great many, m'Lord."
"They worry me, Rabban."
"Worry you?"
"Oh . . . ninety per cent of them are of no concern. But there are always a few . . . Houses Minor and so on, people of ambition who might try a dangerous thing. If one of them should get off Arrakis with an unpleasant story about what happened here, I'd be most displeased. Have you any idea how displeased I'd be?"
Rabban swallowed.
"You must take immediate measures to hold a hostage from each House Minor," the Baron said. "As far as anyone off Arrakis must learn, this was straightforward House-to-House battle. The Sardaukar had no part in it, you understand? The Duke was offered the usual quarter and exile, but he died in an unfortunate accident before he could accept. He was about to accept, though. That is the story. And any rumor that there were Sardaukar here, it must be laughed at."
"As the Emperor wishes it," Rabban said.
"As the Emperor wishes it."
"What about the smugglers?"
"No one believes smugglers, Rabban. They are tolerated, but not believed. At any rate, you'll be spreading some bribes in that quarter . . . and taking other measures which I'm sure you can think of."
"Yes, m'Lord."
"Two things from Arrakis, then, Rabban: income and a merciless fist. You must show no mercy here. Think of these clods as what they are—slaves envious of their masters and waiting only the opportunity to rebel. Not the slightest vestige of pity or mercy must you show them."
"Can one exterminate an entire planet?" Rabban asked.
"Exterminate?" Surprise showed in the swift turning of the Baron's head. "Who said anything about exterminating?"
"Well, I presumed you were going to bring in new stock and—"
"I said squeeze . Nephew, not exterminate. Don't waste the population, merely drive them into utter submission. You must be the carnivore, my boy." He smiled, a baby's expression in the dimple-fat face. "A carnivore never stops. Show no mercy. Never stop. Mercy is a chimera. It can be defeated by the stomach rumbling its hunger, by the throat crying its thirst. You must be always hungry and thirsty." The Baron caressed his bulges beneath the suspensors. "Like me."
"I see, m'Lord."
Rabban swung his gaze left and right.
"It's all clear then, Nephew?"
"Except for one thing. Uncle: the planetologist, Kynes."
"Ah, yes, Kynes."
"He's the Emperor's man, m'Lord. He can come and go as he pleases. And he's very close to the Fremen . . . married one."
"Kynes will be dead by tomorrow's nightfall."
"That's dangerous work, Uncle, killing an Imperial servant."
"How do you think I've come this far this quickly?" the Baron demanded. His voice was low, charged with unspeakable adjectives. "Besides, you need never have feared Kynes would leave Arrakis. You're forgetting that he's addicted to the spice."
"Of course!"
"Those who know will do nothing to endanger their supply," the Baron said. "Kynes certainly must know."
"I forgot, "Rabban said.
They stared at each other in silence.
Presently, the Baron said: "Incidentally, you will make my own supply one of your first concerns. I've quite a stockpile of private stuff, but that suicide raid by the Duke's men got most of what we'd stored for sale."
Rabban nodded. "Yes, m'Lord."
The Baron brightened. "Now, tomorrow morning, you will assemble what remains of organization here and you'll say to them: 'Our Sublime Padishah Emperor has charged me to take possession of this planet and end all dispute.' "
"I understand, m'Lord."
"This time, I'm sure you do. We will discuss it in more detail tomorrow. Now, leave me to finish my sleep."
The Baron deactivated his doorfield, watched his nephew out of sight.