''Halo: The Cole Protocol'' is the sixth novel based on the ''{{Franchise/Halo}}'' Universe, and was written by Creator/TobiasBuckell. It was the last novel published under the contract with Tor Books and has been available to the public since November 25th, 2008. The official plot summary:

"In the first, desperate days of the Human-Covenant War, the UNSC has enacted the Cole Protocol to safeguard Earth and its Inner Colonies from discovery by a merciless alien foe. Many are called upon to rid the universe of lingering navigation data that would reveal the location of Earth. Among them is Navy Lieutenant Jacob Keyes. Thrust back into action after being sidelined, Keyes is saddled with a top secret mission by ONI. One that will take him deep behind enemy lines, to a corner of the universe where nothing is as it seems.

Out beyond the Outer Colonies lies the planet Hesiod, a gas giant surrounded by a vast asteroid belt. As the Covenant continues to glass the human occupied planets near Hesiod, many of the survivors, helped by a stronghold of human Insurrectionists, are fleeing to the asteroid belt for refuge. They have transformed the tumbling satellites into a tenuous, yet ingenious, settlement known as The Rubble and have come face-to-face with a Covenant settlement of Kig-Yar...yet somehow survived.

News of this unlikely treaty has spread to the warring sides. Luckily for the UNSC, this uneasy alliance is in the path of the SPARTAN Gray Team, a three man renegade squad whose simple task is to wreak havoc from behind enemy lines in any way they see fit. But the Prophets have also sent their best, most ambitious and ruthless Elite, whose quest for nobility and rank is matched only by his brutality... and who will do anything to secure his Ascendancy and walk the Path."

!!This novel contains examples of the following tropes:

* ActionGirl: Adriana-111.
* AsskickingEqualsAuthority[=/=]AuthorityEqualsAsskicking: Sangheili/Elite society is meritocratic, meaning that those who perform great deeds (re: military success) advance in society. Kaidons (feudal lords) accept assassination attempts as tests of their ability to lead, for "a kaidon who cannot defend himself is incapable of leadership". [[spoiler: Also, Keyes' actions in the Battle of the Rubble convince Admiral Cole that he's too good to lose, and skip promotes Keyes from Lieutenant to full Commander]].
* BullyingADragon: A bunch of locals try to pick a fight with Adriana-111 in a bar. While they didn't know she was a Spartan-II, she was over six feet tall and looked strong enough to snap a man in half with her bare hands.
* CorruptCorporateExecutive: Charybdis IX is run by one, which gives the Insurrectionists a good way to throw off the UNSC's authority.
* DeathFromAbove: Standard Covenant glassing, [[spoiler:which is what inspires Keyes to use the asteroids of the Rubble as weapons against the Jackals and Grunts on Metisette.]]
* DoomedHometown: Madrigal, which the Rubble inhabitants are survivors of, was glassed by the Covenant in 2528.
* DrivenToSuicide: Jora, a Zealot, is crippled in a fight, so he decides to kill himself rather than live with the shame. Perfectly justified within Sangheili culture , as living would compel his keep to kill his nephews to prevent the "genetic proclivities of failure" from spreading to future generations. He's also too wounded to do it himself, so someone else has to.
* DysfunctionJunction: To suggest that Prophets should disagree with each other is heresy to the Covenant. The {{irony}} is lost on no one.
* EmpoweredBadassNormal / OneManArmy / SuperSoldier: The book has Spartans, natch.
* FateWorseThanDeath: After Saal, a Zealot, tortures Reth in defiance of orders, Thel 'Vadamee orders him to scar himself with the Mark of Disobedience, which Thel says is worse than death. He'll allow Saal to kill himself later before they destroy his body to prevent him from bringing shame on his keep.
* GambitPileup: ''Big'' time. Basically, the novel boils down to around a dozen plans colliding at once, and everyone trying to crawl out of the ensuing clusterfuck.
* HeroicBSOD[=/=]VillainousBSOD: Zhar, one of the Elite Zealots, begins to basically shut down after learning that the Prophet of Truth went behind the Prophet of Regret's back. [[spoiler: He even tries to kill them when it appears that they're going to order his execution, when all he did was follow their commands.]]
* HonorBeforeReason: The Elites are portrayed as this to the [[UpToEleven eleven]].
* {{Irony}}: Thel kills Zhar, his best friend, [[spoiler:when he tries to kill the Prophets of Regret and Truth with his sword for looking like they're about to execute them for following orders]]. This action spares Thel's life, and he is left wondering who in their right minds would dare to rebel so against their leaders. Come ''VideoGame/{{Halo3}}'', Thel, now [[HeelFaceTurn the Arbiter]] and leader of the [[DefectorFromDecadence Covenant Separatists]], [[spoiler:kills the Prophet of Truth with his own energy sword, the very same Prophet whose life he saved on that day]].
* LaResistance: The Insurrectionists.
* {{MacGuffin}}: The Cole Protocol.
* MadLibThrillerTitle: As seen above. Justified, though, as the Cole Protocol has been referenced since the earliest Halo works.
* TheMole: [[spoiler: Lieutenant Badia Campbell.]]
* OhCrap: Adriana gets a good one when she realizes that she's alone, and surrounded by ''ten thousand'' Grunts.
-->Oh shit.
* PlanetSpaceship: At the end, the inhabitants of The Rubble, survivors of the Covenant invasion of their system, convert a large asteroid into an evacuation ship to get everyone safely to UNSC space.
* ProudWarriorRaceGuy: The Elites, taken to wall banger levels.
** Reth, the Jackal leader, even says that the Elites are insane. Then again he comes from a race of space pirates...
** The Prophet of Regret also later notes that Elite honor is insane.
* RightHandVersusLeftHand: The Prophets competing plans smash HEAD on.
* TakeThat: A subtle one to the torture scenes of ''Literature/HaloContactHarvest'', with ONI spook Akio Watanabe's denouncement of torture and those who use it.
* TheRevolutionWillNotBeCivilized: Averted along with TheRevolutionWillNotBeVilified. The Insurrectionists have arguably justified intentions, but their attempts to continue the war during the genocidal war with the Covenant is rather stupid.
** In the other books, it's quite uncivilized, though.
** Definitely uncivilized with the rioting on Charybdis IX, [[spoiler:wherein numerous ONI operatives, pilot Jeffries, and Major Watanabe all lose their lives to the mob.]]
* [[spoiler: RewardedAsATraitorDeserves: Peter Bonifacio is left to die when he fails to get the navigation data to Reth.]]
* RuleOfDrama: Invoked In-Universe. During his debriefing, an ONI officer is flipping through Keyes report with exaggerated slowness. Keyes notes that it's drama, meant meant to make him nervous; but also notes that it's working.
* SmugSnake: Peter Bonifacio. Actually, all of the Insurrectionists seem to be this. Their myopic independence-based patriotism and condescending attitude can really grate.
** Conversely, this is how the Insurrectionists see the UNSC, apart from basically considering them to be fascists.
* SpaceMarine: Spartans, as above, alongside the more BadassNormal [=ODSTs=].
* SpacePirates: The Jackals.
* VillainProtagonist: Thel 'Vadamee, the [[HeelFaceTurn future Arbiter]]. At this point he is still a loyal and zealous servant of the Prophets. Though by the end of the story, he starts showing some hints of doubt about the motives of the Prophets.
* WarriorPoet: Veer, one of the Elite Zealots, spends raids looking for oddities on human ships for his war poems.
* WhatHappenedToTheMouse: Veer. He disappears partway through the novel to pilot a Jackal shuttle (or something similar), then is never mentioned again.
* YourTerroristsAreOurFreedomFighters: The Outer Colonies mainly think this of the Insurrection, though considering that things like Charybdis apparently happen on a regular basis you can't really blame them.