Which author wrote the Halo novel Ghosts of Onyx?

Eric Nylund wrote the Halo novel Ghosts of Onyx.

Published in 2006, Ghosts of Onyx is the fourth Halo novel and expands the story of the Spartan program, the United Nations Space Command, and the Forerunners. Its plot follows major military and scientific developments during the Human-Covenant War.

Nylund had already written The Fall of Reach and First Strike, making Ghosts of Onyx his third published Halo novel. The book helped connect the games’ military action with broader background about Spartan training and advanced Forerunner technology.

It is sometimes confused with later Halo novels by Tobias Buckell or Karen Traviss. Those authors contributed to the franchise, but Ghosts of Onyx is specifically credited to Eric Nylund.