Against Gravity — Gary Gibson

Live long enough, and this could be your future...

It is the late 21st century, and it is a very different world. Meet Kendrick Gallmon, survivor of The Maze, a secret research facility where thousands of political prisoners became unwilling guinea pigs in experiments to create the perfect soldier. Kendrick Gallmon is trying to pick up the pieces of his life, even though he knows his nervous system, which is riddled with unstable nanotech augmentations, is slowly killing him. Then one day, his heart stops beating, forever. A ghost urges him to return to the source of all his nightmares--a long-abandoned military complex filled with the entirely real voices of the dead...