Halo: Cryptum by Greg Bear

The first novel in the Forerunner Saga trilogy by science fiction legend Greg Bear-set in the Halo universe and based on the New York Times bestselling video game series!One hundred thousand years ago, the galaxy was populated by a great variety of beings. But one species-eons beyond all others in both technology and knowledge-achieved dominance. They ruled in peace, but met opposition with quick and brutal effectiveness. They were the Forerunners-the keepers of the Mantle of Responsibility, the next stage of life in the Universe's Living Time. And then they vanished. This is their story.
Binding: Paperback / softback