Ghost in the Shell. Shirow Masamune. Kodansha Ltd (Japan), and Dark Horse Manga (U.S.) 2004.
The manga 'Ghost in the Shell', comes securely wrapped in cellophane, with a parental advisory warning label on the front c over. Yes, it includes a little of everything you would expect when seeing a parental advisory.
It is an excellent book. Basically it is a serious, adult science fiction (cyber-punk or post-cyberpunk) illustrated novel. Or put another way, it is an adult comic book. The setting is a future in which the technology and the human have begun to overlap. Some humans chose to have their bodies partially or entirely replaced by robot bodies, making them cyborgs. These bodies are indistinguishable from human bodies (except for the weight), and in some cases they have enhanced strength, hidden attached weapons, and other devices. Also there are robots which likewise look, and largely behave, like humans. The difference can often only be determined by a scan to detect a 'ghost', basically the spirit, residing inside the body.
The main character is Major Motoko Kusanagi, of 'section 6', a special forces unit of the Japanese police. Most of the story is an excellent police/military/spy thriller-adventure. But inlaid with the action is philosophic-scientific speculation on several questions, primarily: 'What is human?'. Masamune references engineering, biology, chemistry, Buddhism, the Kabbalah, western philosophy, etc.
The main characters are interesting but not always sympathetic, because in their crime-fighting journeys, they are sometimes jaded and unsympathetic toward the victims. Does this simply mean they are sometimes assholes, or is Masamune suggesting their partial or total mechanization is making them less human?