A character dies when his or her hit points drop to -10 or lower. A character also dies when his or her Constitution drops to 0, and certain spells or effects (such as failing a Fortitude save against massive damage) can also kill a character outright.
Death causes the character's soul to leave the body and journey to an outer plane. Dead characters cannot benefit from normal or magical healing, but they can be restored to life via magic. A dead body decays normally unless magically preserved, but magic that restores a dead character to life also restores the body either to full health or to its condition at the time of death (depending on the spell or device). Either way, resurrected characters need not worry about rigor mortis, decomposition, and other conditions that affect dead bodies.