4th Edition Monster Manual
In today's Monster Manual preview, we look at undead in general... and the shambling horrors that are zombies in particular.
From the Monster Manual Glossary:
Undead: Undead are not living creatures; spells and effects that specifically target living creatures do not work against them. Most undead have resistance to necrotic damage, are immune to poison, and are vulnerable to radiant damage. Undead do not need to breathe or sleep.