Target 1 Spellcaster-Type monster you control; until the End Phase, it gains 1000 ATK. Also, until the End Phase, each time it destroys an opponent's monster by battle: You can add 1 "Spellbook" Spell Card from your Deck to your hand. You can only activate 1 "Spellbook of Power" per turn.
Use Spellbook of the Master and select the Spellbook of Power in your graveyard. This allows you to use the effect of Spellbook of Power a second time in one turn, select another target for attack boost and search another Spellbook spell card when it destroys a monster by battle.
If you have a level 7 or higher Spellcaster-type monster, you can use both Spellbook of Power and Diffusion-Wave Motion on it. This will allow it to gain 1000 attack points, attack all monsters your opponent controls, negate the effects of monsters it destroys, and search Spellbooks from your deck equal to the number of monsters that monster destroyed.
Here are some Spellbook spell cards that support the Prophecy Archetype and Spellcasters in general. You can search them when with the effect of Spellbook of Power.