Does "Shield" spell protect against a surprise sneak attack or when flanked?

[Erkenbard the Eyeful]

The Shield spell says the shield "hovers in front of you," but as there are no "facing" directions in the rulebook, it is counted as always covering one in combat. However, sometimes you are flanked or clearly attacked from behind ... when you suffer a surprise sneak attack (i.e. backstabbed). So does the Shield apply in these circumstances?

[Saethori]

You gain the benefits of a physical shield regardless of whether you're flatfooted, flanked, or otherwise not at your full fighting potential, and, since it's typically strapped to your arm, it's actually less flexible to shield blows than a magical floating shield.

I see no reason why the AC gained by the Shield spell would not also apply.

[Pizza Lord]

Saethori is correct. Over the years spell descriptions have been changed and trimmed down. Originally, before Pathfinder, it applied its shield bonus to attacks coming from a 180 degree direction, angled how the caster wished it and changeable at their whim.

Later, it just provides a shield bonus and the description 'hovers in front of you' also had the words 'moves to interpose' or 'moves to intercept'. However, extraneous wording and text has slowly been trimmed over the years as descriptions have been moved to websites. The shield bonus applies to all attacks (that don't ignore shield bonuses or force effects) at pretty much all times.

[JDLPF]

The shield spell provides a shield typed bonus to AC.

Shield bonuses apply to AC and flat-footed AC, but not touch AC.

So unless the enemy is attacking your touch AC, you get the bonus from the shield spell.

Furthermore, this bonus also applies in the event the enemy is using an incorporeal touch attack. The shield spell provides its bonus to AC against these attacks.

[Erkenbard the Eyeful]

Thanks. I had the feeling this was the case, but was wondering if I had perhaps missed optional rules outside of the Core Rulebook and APG regarding it. I like the idea of backstabbing thieves sneaking up behind someone who cannot use a shield, but still ... I can live with the rules outlined in the responses above. Again, thanks.

[toastedamphibian]

Erkenbard the Eyeful wrote:

was wondering if I had perhaps missed optional rules outside of the Core Rulebook and APG regarding it.

Combat Facing

Is 3.5, but looks like it should be fully compatible.

Edit: shield based excerpt

Quote:

A character holding a shield must indicate whether he’s wielding it to the left or right. The shield only adds to the character’s AC against attacks coming from his front area and the flank area on the shield’s side, plus any squares that lie beyond those areas.
The shield spell provides a bonus to AC against attacks from the front area only