SpoilerBlue denotes the 'main series' Green denotes a game not on the mainline. Otherwise, all others are books.
*I recommend just reading a synopsis of this, because it's pretty terribly written for something rather important.
- The Forerunner Saga (Halo: Cryptum, Halo: Primordium, Halo: Silentium) - The Story of the Forerunners' final days.
- Broken Circle - The Story of how the Covenant began, and how it broke
- Contact Harvest -The Story of how the Human-Covenant War began, and Sgt. Johnson's backstory.
- Halo Wars 1 -The Story of the Spirit of Fire
- The Fall of Reach -The Origin Story of the Master Chief and the other Spartan-IIs, and how Reach fell.
- Halo: Combat Evolved
- First Strike -The Story of what happened after Reach and Halo: CE, and before Halo 2
- Halo 2
- Halo 3: ODST -The Story of Alpha-Nine, the "ODSTeam"
- Halo 3
- Ghosts of Onyx -The Story of the Spartan-IIIs begins, and what happened to Blue Team and Dr. Halsey after Reach.
- Kilo-5 Trilogy (Glasslands, Thursday War, Mortal Dictata) -More Dr. Halsey, Blue Team, and the S-IIIs; The Story of what happened after Halo 3
- Last Light -More Blue Team and S-IIIs
- Retribution -Sequel to Last Light
- New Blood -The Story of what happened to the ODSTeam, and how Buck became a Spartan-IV
- Hunters in the Dark -The Story of the Return to the Ark, and the first time Humans and Sangheili (Elites) work together after the war. Spartan Vale's origin story.
- Halo 4 (and Spartan Ops side missions)
- Escalation* -The Story of what happens between Halo 4 and Halo 5.
- Halo 5: Guardians
- Halo Wars 2 -The Spirit of Fire returns, The Story of how the Banished come to power.
- Bad Blood -The Story of what happened immediate after Halo 5, starring Buck and Fireteam Osiris, Master Chief and Blue Team, and the old ODSTeam
- Halo Infinite
Did you leave out Halo Reach on purpose or by accident?