Off Armageddon Reef - David Weber

Here is the saga of humanity reduced, by an implacable alien enemy, to inhabiting a single colony on the distant world of Safehold.

To avoid drawing the attention of the enemy through the busy signals of an industrial civilization, the human rulers of Safehold have taken an extraordinary measure. With mind control and hidden high technology, they have built a religion in which every Safeholdian believes, one designed to keep Safehold society medieval and unnoticed forever. After disagreement about the wisdom and justice of this course, the dissenters were ruthlessly eliminated. Centuries have passed and now, in a hidden chamber on Safehold, an android initiates a rebirth set in motion centuries before. A rebirth that will provide the only remaining humans with their last chance to learn the truth and to rejoin the universe.

It is destined to be a tremendous undertaking, unfolding a story of deception and ignorance, freedom and tyranny, and the liberating power of the truth.

'Nobody does space opera better than Weber' Publishers Weekly