This is just one of those moments in Superman lore that is pretty complex to explain....I'll try my best. Keep in mind that this is argued in a lot of forums and while some of my statements could be false, don't label me as completely "incorrect". Feel free to add on to me and/or explain further: Superman had pretty much depleted his extensive solar reserves in the fight against Doomsday (which also involved Doomsday pounding on him pretty damn badly). At the end of it, Supes went into a coma (and then some). If he'd been left out on a rooftop with sunshine beating down on him, maybe he would've recuperated -- but stupid humans that we are, we sealed him into a coffin and sealed the coffin up in a crypt and otherwise cut him off from the stuff that powers his abilities. So, instead, he eventually died; his soul left the weakening comatose body and everything. As it happens, though, Jonathan Kent was having an out-of-body experience right about then as well, and convinced his adopted son not to go into the light, and so the soul went back in, and -- -- well, that would've been useless *too*, in the long run; if his body had been left there much longer, it would've gradually gotten worse and that would've been it. There three other "supermans" who think they are superman. Superboy, who was created by Superman's stolen DNA. Cyborg Superman who was sent from Krypton (I think, I truly forget how his character emerged) and the Eradicator who was cosmic energy similar to that of Superman who wished to use Superman's body. But that's when the robot from Krypton hauled Superman's body down to the Antarctic, right under the hole in the ozone layer where intense yellow sunlight comes streaming in *unfiltered*, and, man, Supes started recuperating. It took time, sure, and when he finally regained consciousness his powers still had a lot of recharging to do. But he was on his way back. Now, if things had gone a little differently, forget about it. If he'd exhausted his solar reserves *without* defeating Doomsday, and then had his head ripped off his powerless body -- dead. If his soul had just gone on to the afterlife, or if his body had remained cut off from the rays of a yellow sun just a little longer -- dead. But he got lucky. So basically in other words: NUTSHELL VERSION: Superman died. Erad goes to the tomb to take possession of the body. Because of Pa's heartattack and his interaction with Kal in the afterlife, Kal's soul hadn't entirely fled the body; therefore Erad can't take the body. Erad forms a body for himself by transmuting mass in the tomb. Erad takes the body to the Fortress of Solitude and puts it in a sun bathing machine so he can feed of it's energies. The combined sun energy and the complete return of the soul to the body due to Pa's intervention bring Superman back to life. It was a once in a lifetime lucky combination of matter and spirituality that can likely never be repeated. There it is....i think.