2 RE RE) ok
3 RE RE) ty
4 RE RE) I've enchanted at least 10 level 37 books and i haven't got any prot II or melee or range book.
The Legendary books are pretty bad. Almost everyone knows to not purchase them unless you have nothing better to do. Common and Rare books are the best way to go.
By purchasing Legendary, it increases the chances of getting most of the enchantments. But, things like Proj. Prot and Aqua Affinity are given the higher chances for some reason.
The only thing Legendary books are good for is Strength for all weapons. Common and Rare books both have a chance of getting Strength; but if you do get Strength, it'll only be for iron weapons and armour.
Common is the best way to go if you're looking for offensive enchantments ( excluding strength ), while on the other hand, Rare books are the best way to go if you're looking for defensive enchantments such as Protection.
Moral of the story: don't get Legendary books unless you have nothing better to do. I've gotten things like Strength, Jump Boost III, Flame, Regen, etc from Rare and Common. The two best things I've gotten from Legendary are Strength for all weapons and Power IV.