Because just like the Holtzman field is the do-it-all for Dune technology, prana-bindu is your go-to if you need to explain any (super)human ability.

Whether you want to calm your nerves, decide your kid's sex, or counteract some chaumurky or chaumas, you need some prana-bindu training in your life.

Imagine the suffocating feeling of being engulfed by sand. You're caught in a sandslide, no escape from reality. You gasp for air, want to open your eyes and see, but the dune swallowed you whole. What do you do?

Well, if you're properly trained like the Lady Jessica was, you can calmly wait for someone to dig you out - and the reason you have time to wait is that you can slow your metabolism down to almost nothing.

She's been caught in the sandslide, he thought. Buried in it. I must be calm and work this out carefully. She won't smother immediately. She'll compose herself in bindu suspension to reduce her oxygen needs. She knows I'll dig for her.
— Dune [1965]

What makes prana-bindu the arguably coolest and most powerful discipline is the sheer scope of control it grants over every aspect of human existence - from individual muscle fibers and nerve endings to the perception of time itself.

While the expanded universe books limit themselves to people doing generic prana-bindu exercises or calming themselves down with prana-bindu breathing, or the occasional display of prana-bindu control of their bodies, the original six books (and the Dune Encyclopedia) go into quite a bit of detail about the spectrum of mastery.

Prana vs Bindu

While most of the time you would hear them as a pair, it's made clear that they are two separate disciplines, and while yes, adept practitioners use them in tandem, they are still two separate skill trees.

"Today you panicked," she said. "You know your mind and bindu-nervature perhaps better than I do, but you've much yet to learn about your body's prana-musculature.
— Jessica to Paul, after he dug her out, Dune [1965]

And that's pretty much how the Terminology of the Imperium explains them, too.

BINDU: relating to the human nervous system, especially to nerve training. Often expressed as Bindu-nervature. (See Prana.)
PRANA (Prana-musculature): the body's muscles when considered as units for ultimate training. (See Bindu.)
TRAINING: when applied to Bene Gesserit, this otherwise common term assumes special meaning, referring to that conditioning of nerve and muscle (see Bindu and Prana) which is carried to the last possible notch permitted by natural function.
— Dune [1965]

As mentioned in the "Languages of Dune" summary, prana-bindu is derived from Sanskrit. Prana, meaning life force, and bindu, meaning point, so together they'd mean focusing the life force.

They're very much interconnected, so you'll almost always see them used together, but some abilities would obviously rely on one over the other.

• Jessica’s aforementioned suspension, manipulating one’s time perception, detailed perception of others, and analytical and memory systems would mostly fall under bindu.
• While the Voice, the combat applications like weirding way, and other physical feats would require more prana training.

Origins

While it sounds to be an offshoot of eastern philosophy, prana-bindu is not an ancient practice that the Bene Gesserit preserved.

Appendix I of the original Dune explains what the Sisterhood was up to, right after the Butlerian Jihad.

Certainly, this is the time in which they consolidated their hold upon the sorceresses, explored the subtle narcotics, developed prana-bindu training and conceived the Missionaria Protectiva, that black arm of superstition. But it is also the period that saw the composing of the Litany against Fear and the assembly of the Azhar Book, that bibliographic marvel that preserves the great secrets of the most ancient faiths.
— Dune [1965]

The Encyclopedia then further expands on this, connecting it back to Hindu and yogic philosophy - albeit noting a stark difference in the perception of the world.

The clearest analysis to date of the system is in Reverend Mother Maxius Oaire Beeghler's Prana and Bindu: Control for Power, She identifies the bask premise of the training as that found in an ancient Terran religion in which the path to the truth was called Sabda and closely resembled what is known to the Bene Gesserit as the "Way." Sabda allowed an internal realization of truth which identified the knower with an immutable reality. The Bene Gesserit Way also identifies the knower with reality, but denies immutability. Thus the Bene Gesserit axiom: "The purpose of argument is to change the nature of truth."
— Dune Encyclopedia [1984]

Sabda is referred to as the inner sound, the audible life stream, or the word.

The price of perfection

Balance

The same conditioning processes, however, are used to attain both Sabda and the Way. The key to both is achieving harmony and tranquility through establishing balance within the individual.
— Dune Encyclopedia [1984]

This balance is achieved through rigorous regimens that organize and control both body and mind, as well as a significant amount of meditation and introspection, to gain an understanding of oneself.

"My mind controls my reality." His eyes glittered, and he repeated it, louder this time: "My mind controls my reality!"
"That is the beginning of prana-bindu balance," Jessica said. "It is only the beginning, though."
— Farad'n to Jessica, Children of Dune [1976]

Training

According to the Encyclopedia, structured training takes a decade - and we know from the Lady Jessica that ideally it should start in childhood.

"It would've been better to begin this when you were much younger," Jessica said. "It'll be harder for you now, and it'll take much longer."
— Jessica talking to Farad'n, Children of Dune [1976]

No surprise, knowing the task: practitioners must rewire their entire nervous system.

The body does things of itself sometimes, Paul, and I can teach you about this. You must learn to control every muscle, every fiber of your body.
— Dune [1965]

These automatic processes - heartbeat, digestion, cellular repair, hormonal cascades - all must be brought under conscious command. You're learning to manually operate systems that evolution designed to run without conscious input.

When it comes to the body, the progression seems to be from big to small.

You need review of the hands. We'll start with finger muscles, palm tendons, and tip sensitivity.
— Jessica to Paul, Dune [1965]

[…] starting with some elementary prana-bindu exercises for the legs and arms, for your breathing. We'll leave the hands and fingers for later.
— Jessica to Farad'n, Children of Dune [1976]

And to support the mind, the Encyclopedia tells us that Sisters would learn "one of thirty-three postures, each appropriate to a specific type of analytical work."

Variations and Evolution

While it might've started with the Bene Gesserit, they're not the only ones who have mastered their muscles and their nerves.

The Ginaz School produces swordmasters (like Duncan Idaho) with a complete focus on physicality and combat.

The Honored Matres push speed and sexuality to disturbing extremes, creating addictive responses that are more enslaving than any drug.

But Odrade shared the excitement of the Breeding Mistresses. That speed! Add that to the nerve-muscle training, the great prana-bindu resources of the Sisterhood! What that might create lay wordlessly within her.
— Chapterhouse: Dune [1985]

And then we have the Tleilaxu, with their ambition to genetically replicate all of the gains (and even surpass them) without any of the work required.

The Reverend Mother drew back, and Scytale saw her reassessing him. They were all products of profound prana-bindu training, capable of muscle and nerve control that few humans ever achieved. But Scytale, a Face Dancer, had muscles and nerve linkages the others didn't even possess […]
— Dune: Messiah [1969]

"The Tleilaxu ambition is to produce a complete prana-bindu mimic," her advisor had suggested.
[…]
"We already know that what an Ixian Probe does mechanically, the Tleilaxu do with nerves and flesh."
— Taraza to Waff, Heretics of Dune [1984]

The spectrum of mastery

Mind and memory

Let's start with a passive buff: practitioners develop multiple memory systems.

Conscious recall is enhanced to perfection - they can reproduce any conversation verbatim, even simulating exact tone and pitch.

Time perception itself becomes malleable. Adepts - so the Encyclopedia tells us - can release "themselves from the artificial confines of the human notion of time." This way,

+10 to perception

Where others only look, those trained in prana-bindu can see - and they see everything.

Paul sat back. He had used the questions and hyperawareness to do what his mother called "registering" the person.
— Dune [1965]

The Encyclopedia explains that practitioners can recognize registered individuals regardless of appearance changes, even detecting Face Dancers and gholas through "non-human characteristics which were visible if you knew how to look for them."

You might remember, of course, that this kind of seeing is also a prerequisite for using the Voice effectively.

Controlling others

And while we talked about the Voice a few months ago, we didn't mention its much more insidious cousin, what the Lady Fenring called hypno-ligation.

"Indeed, and it's obvious we must have a hold on him. I'll plant deep in his deepest self the necessary prana-bindu phrases to bend him."
— Dune [1965]

This technique of planting subconscious responses to triggers appears once more at the end of the original book, just before Paul faces down Feyd.

Jessica leaned close to Paul, pitched her voice for his ears alone: "One thing, Son. Sometimes a dangerous person is prepared by the Bene Gesserit, a word implanted into the deepest recesses by the old pleasure-pain methods. The word-sound most frequently used is Uroshnor. If this one's been prepared, as I strongly suspect, that word uttered in his ear will render his muscles flaccid and—"
"I want no special advantage for this one," Paul said. "Step back out of my way."
— Dune [1965]

Controlling oneself

Jessica's bindu suspension saves her life in the sandslide, but that's just the beginning.

The dao dormancy trance mentioned in the Encyclopedia pushes even further, reducing life signs until the practitioner appears dead to all but the most sophisticated detection.

Most famously, practitioners can neutralize poisons at the cellular level - the ultimate test comes during the Reverend Mother initiation with the Agony, where this cellular awareness means the difference between transcendence and death.

I think it's also widely known that Bene Gesserit can determine the sex of their offspring. We know Jessica decided to have a son instead of a daughter.

But most incredibly, age becomes negotiable through cellular control.

"I've already sent word to the Sisterhood that Alia practices the unthinkable. Look at her! She's not aged a day since last I . . ."
— Jessica talking to Leto II, Children of Dune [1976]

The God Emperor's ultimate form

Leto II's transformation demanded prana-bindu mastery beyond any previous practitioner.

The sandtrout weren't just an external covering - they merged with his nervous system, requiring conscious integration of each organism into his expanding awareness.

He got to his feet, turned to run back toward the hut and, as he moved, found his feet moving too fast for him to balance. He plunged into the sand, rolled and leaped to his feet. The leap took him two meters off the sand and, when he fell back, trying to walk, he again moved too fast.
Stop! he commanded himself. He fell into the prana-bindu forced relaxation, gathering his senses into the pool of consciousness. This focused the inward ripples of the constant-now through which he experienced Time, and he allowed the vision-elation to warm him. The membrane worked precisely as the vision had predicted.
— Children of Dune [1976]

Without this total body awareness extending far beyond normal human boundaries, the sandworm transformation would have consumed his consciousness along with his humanity.

Instead, he managed to become an almost immortal being.

The ultimate discipline

Leto II's transformation displays applications beyond the human form entirely. The Honored Matres achieve speeds surprising the Bene Gesserit. The Tleilaxu are working on perfect replication.

The reason I love prana-bindu is that it represents humanity's refusal to accept limitations.

It's the ultimate expression of human will - the determination to master not just our environment, but our very selves.