Silent Death

Silent Death is a Fallout, Fallout 2, Fallout Tactics and J.E. Sawyer's Fallout Role-Playing Game Perk.

While Sneaking, if you hit a critter in the back, you will cause double damage using a HtH attack. Silent Death is just that kind of perk.
 * Note: A weaker equivalent of this Perk called "Backstab" appears in Lionheart. It has also been carried over to Fallout 3 in the form of sneak attack criticals, which does not require any perk.

This perk will not double the damage caused by a critical hit and critical hits do at least two times normal damage. This means that the slayer perk is much more useful and after picking that perk, this perk becomes useless.