Battle Book (3.5e Equipment)
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Wizards often use this weapon which doubles as a spellbook. The tome is larger than normal (though it holds no more than a common spellbook) and heavy, wrapped in toughened leathers and brass bindings and supports. It can be used as a bludgeoning weapon, balanced just right to be swung around like a club. Likewise it can be enchanted as a weapon. It has enough metal in it to count as the damaging part of the weapon, and can have adamantine and the like added to it.
See Blessed Battle Book for its wondrous item based magic weapon.