 Greg Bear was 343 Industries' first choice to write a trilogy of books based on the history of the Forerunners and another mysterious race known as the Precursors.Bear had been writing a book entitled "Hull Zero Three" when he was approached to be the trilogy's author.At the first meeting with Bear regarding the book, he was told that it should be a "classic Greg Bear giant – in the vein of Eon, Anvil of the Stars and so on", but inspired by "Halo" and its extended universe.