Dooku piloted his Sith Infiltrator through the solar system toward his destination, running a Sith holocron between his fingers. A Sith holocron that he had taken...borrowed...stolen from the Jedi Archives. A Sith holocron that triggered his reminiscence again.
After Sifo-Dyas left him in the Senate halls, Dooku realized that there was some truth to what Sifo-Dyas told him, that his method of applying the Unifying Force was meeting formidable resistance. But rather than abandon the Unifying Force, whose predictive guidance had seen him well through so many decades of Jedi activity, Dooku decided to change the way he used it. He recognized that his current method was alienating all those around him, so he took a different tack. He decided to pore through the Jedi Archives, utilizing the expertise of his friend and former confidante Jocasta Nu.
He appealed to her haughty pride in her knowledge of the ancient secrets of the Sith, persuading her to grant him access to the sealed vault of Sith holocrons. He reasoned that studying the Sith Archives would be the best way to comprehend the mysterious ways by which the dark side cloaked itself from the Jedi. She agreed and set aside a private study room for him, which he occupied for hours at a time, leaving only to eat or sleep. She had not yet heard about the Council's suspicions of Dooku. Or if she had, she exercised her considerable ability not to listen to then when data from the outside world conflicted with her understanding of the order of the universe.
At first, she acted as the embodiment of a persnickety stickler for regulations that nearly all members of the Jedi Order knew the head librarian to be. She supervised his researches tenaciously, tracking each holocron that Dooku examined...for how long he looked at it...what data he accessed on it...forcing him to confine his studies to holocrons containing relatively innocuous Sith legends and credos to avoid raising suspicion. He hid his rageful impatience at her micromanagement beneath a smooth veneer of obsequious obedience and flattery.
Fortunately, his ploy bore fruit within a few weeks. After having Dooku consistently stroke her considerable ego for what may have been the first time in decades, she became increasingly lax with him, eventually allowing him to take Sith holocrons for study without formally checking them out or having them scanned by the security droids. This lack of oversight gave him unfettered and unchecked access to the darkest secrets of the Sith present in the Jedi Archives. The more he studied the ways of the Sith, the more he allowed his consciousness to absorb their malevolent teachings, the more he felt compelled to approach the source of the dark Force currents rather than rip through it by the sheer force of his mediations.
Dooku became intrigued by the Sith doctrines and how they seemed prophetic about the current stagnation in the Galactic Republic. As he clutched a particular Sith holocron, Dooku came to understand that the Sith believed in the use of power as a means toward attaining perfection. The destruction that followed in their wake resulted in the imperfection of others, not from an inherent wish to destroy. The Sith ensured that each life remained strong, rather than allowing weakness and idiocy to corrupt the Force and the life within it.
A heretical thought took root in Dooku's mind. Perhaps the clouding of the Jedi Order's Force sight resulted not from some active dark side machinations, but from the weakness of the Jedi themselves, which was exposed by the increasing dark side Force activity!
The thought enraptured Dooku, eroding decades of training in Jedi ethics almost instantly, replacing it with a single maxim: perfection of the fittest. A maxim that summarized the pure kernel of Sith lore, passed down untainted for thousands of years. And with that knowledge, a flash of the Unifying Force revealed to him the identity of the remaining Dark Lord of the Sith. A Sith in the Chancery would not be satisfied as anything but its head. He would subordinate himself to no one, be the servant of nothing. The Sith Lord imust/i be the Supreme Chancellor: there was no other possibility.
But Dooku's studies convinced him to join the Sith, rather than expose them. The Sith teachings agreed with his sense of self-importance, which his Jedi discipline forced him to bury. They gave him focus, allowed him to comprehend why he had felt so stifled under the Jedi's strict codes of conduct. They liberated him, showing him a way to live to his fullest potential – to rule far more than a few mewling younglings. Yes, the way of the Sith held much greater promise for Dooku, and he would force himself into it, threatening to expose the Chancellor if he did not allow Dooku to be initiated into its secrets.
With that decision, a new equilibrium settled over Dooku's mind. Suddenly, the Unifying Force became clear for him. He no longer had to battle through waves of dark energies to understand the coming storm. Now, it unfolded before him in crystal clarity. And he was at its center. Commanding armies of men and droids. Beating the Jedi into submission. Winning whole sectors of systems to his leadership. Penetrating to the very heart of the Galactic Republic. A smile passed over his face as he leaned fatuously back in his chair, the tension of the last few months released utterly from his body.
Over the next few days, Dooku surreptitiously deleted planets from the Jedi Archives that had been mentioned in the Sith holocrons so that no one would be able to trace his movements. He also removed the Sith holocrons from the Jedi Archives so that the Jedi would be unable to harass the Sith, as they had done for millennia, nearly to the point of extinction. Once he removed the last Sith holocron from the Archives, Dooku strode purposefully toward the Chancellor's office, twisting the Sith holocron between his fingers as he left in a brazen act of defiance. Jocasta Nu never even looked up at him as he walked past, trusting him to return the holocron when he was finished with it.
The same Sith holocron worked through Dooku's fingers as he entered orbit around the planet Dagobah, soon to be the final resting place of Master Sifo-Dyas.