So this is has been bugging me a lot, these ludicrous claims that “You have to do your homework to understand the game”.
IT IS SIMPLY FALSE.
The books are almost exclusively present to enrich the greater lore, and are in no way needed to play and understand the mainstream games.
Let’s look at a few examples:
Broken Circle: A story documenting the creation of the Covenant, and rediscovery of a lost sect of Sangheili.
Hunters in the Dark: Chronicling Vale’s first experience with Forerunner technology, and why she was granted spartanhood. Zero impact on games.
Last Light: Follows a homicide detective in her search for a serial killer, while chronicling events regarding Spartans Fred, Kelly, Linda, Tom, Olivia, and Lucy, post Glasslands, pre Halo 5. Zero impact on games. (Although it has many interesting ties to other extended lore.
New Blood: Follows the story of how Buck becomes a Spartan IV. Shows why Buck does not want to be a team leader. Let’s give this about a 2 on a scale of 0 to 100 on how it affects the game story.
Saint’s Testimony: A short story analyzing the legal ramifications of decommissioning an AI before the onset of Rampancy. Zero impact on games story.
Shadow of Intent: A short story chronicling the downfall of High Charity and the actions of Rtas. Has a badass grunt. Zero impact on game story.
Hunt the Truth: A “podcast” from a journalist who unravels the truths of the Spartan II program, and his precarious relationship with ONI. As of now, this has little impact on the game story, but that may change with future iterations.
Halo: Nightfall: A digital release of Locke trying to find some element on the remains of Installation 4 (Alpha Halo, the Halo from CE). Zero impact on game story.
Unless I have missed something, that sums up the entirety of the Extended Universe between Halo 4 and Halo 5: Guardians. Not a single element is needed for the story. The extended universe is there to expand on backstories, allow us to understand and get to know characters better. Flesh out political motives behind otherwise apparently benign actions. Essentially, it helps create a richer, more believable world.
Just because these materials are available, does not mean they are necessary. Take Contact Harvest, for example. It focuses on part of Sgt. Avery Johnson’s experiences while also shedding light on the San Shyuum’s motives behind their declaration of Humanity’s extermination. Is this story essential to read to understand Halo? No, but for those who want to dig deeper, it reveals plenty of answers.
There have been books, most obviously The Forerunner Trilogy, That are the exception. Where lore lovers adore this series, it does melt the lines between “need to know” and “extra enrichment”. While many agree that Halo 4 had the most complex and fulfilling story in scifi terms, much of this was a direct result of the Forerunner Trilogy, and therefore wad hard to digest by the average player. People complained, 343i listened, and as my above descriptions indicate, books published later were designed to evade such issues.
I’ve seen you tubers like theactman and LNG complain about it but in all reality, they only say this in attempt to further condemn 343i. Theactman has said himself that he hasn’t ready any of the books, so how can he even know!!! Youtubers like this only sow discontent among the community, where in truth they don’t “do their homework” (catch my drift?).
Tl;dr:
The EU is not necessary to understand the games. It only enriches the greater universe for those who want it.