Does the Shroud's Lore bonuses sack with each other?

For example,

Fire Lore, Greater Fire Lore, Superior Fire Lore for a 18% Crit chance and a +1 to your already existing spell crit multiplyer.

Or does it only gives 9% and +0.5 to already existing spell crit multiplyer.

Does this stack with the enhancements you can take and does it stack with the non-shroud Lore items?