There are 6 books in the Halo (Standalones) series. The newest book is The Rubicon Protocol which came out in 2022.

1
Contact Harvest

Book cover of Contact Harvest
The New York Times bestseller—part of the expanded universe based on the award-winning video game series Halo!

2524. Harvest is a peaceful, prosperous farming colony on the very edge of human-controlled space. But humanity has unknowingly trespassed on holy ground—straying into the path of the aggressive, theocratic empire known as…
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2
Broken Circle

Book cover of Broken Circle
The New York Times bestselling series based on the blockbuster Xbox® games!

Centuries before the Human-Covenant War would rage across the galaxy, a similar conflict erupted between the Prophets and the Elites—two alien races at odds over the sacred artifacts left by the powerful Forerunners, who disappeared eons ago. Although…

3
Hunters in the Dark

Book cover of Hunters in the Dark
The New York Times bestselling series based on the blockbuster video game for Xbox!

It is 2555, more than two years after the Master Chief went missing-in-action following a decisive conflict on Installation 00—the massive, extragalactic Forerunner construct known as the Ark—as part of the final chapter in humanity’s bloody…

4
Legacy of Onyx

Book cover of Legacy of Onyx
An original full-length novel set in the Halo universe and based on the New York Times bestselling video game series!

Molly Patel was only seven years old when the alien alliance known as the Covenant destroyed her homeworld and killed her family. As one of the few to escape the…

5
Outcasts

Book cover of Outcasts
An original novel set in the Halo universe—based on the New York Times bestselling video game series!

2559. Formerly one of the Covenant’s greatest and most fearsome warriors, Arbiter Thel ‘Vadam is now allied with his former human enemies while deeply entrenched in leading the Sangheili people to a new…

6
The Rubicon Protocol

Book cover of The Rubicon Protocol
USA TODAY BESTSELLER

An original novel set in the Halo universe—based on the New York Times bestselling video game series!

A HALO INFINITE STORY

December 2559. Humanity has its back against the wall after the United Nations Space Command flagship Infinity drops out of slipspace into a devastating ambush launched…