Throughout history, states have tried to create the perfect combatant, a solider with superhuman physical and cognitive features, akin to those of comic book superheroes. However, current innovation has little to do with past ideas of the ideal super-soldier, with the new tools of warfare going far beyond simple technological advancement. We are raising the prospect of a human enhancement revolution that will change the way war is fought and may profoundly alter the foundations upon which our modern societies are built. This book discusses the full ethical implications of these new technologies, and is a unique contribution to current debates on the morality of warfare. When analyzed from an ethical viewpoint, the development and use of capacity-increasing technologies in the military is far more complex than it first appears, and should be considered a significant ethical dilemma. Enhancing soldiers' capacities might be considered a moral obligation on the part of the military but such technologies might also end up harming the fundamental moral principles of warfare. Without condemning them as immoral and inadmissible, Caron proposes a nuanced and balanced appraisal of capacity-increasing technologies in the military, and suggests that they are tools that ought only to be used when compliance with strict moral criteria has been reached.