Trap spellbook

Trap spellbook was an alteration spell that protected a book, more often a mage's spellbook, from being being opened by anyone other than its owner.

Effects
In a manner similar explosive runes, trap spellbook created arcane runes upon the targeted book, that when opened by anyone but the spell's caster, caused a massive explosion. There was little chance anyone could see the effects of the spell, unless they were aided by a divination or a similarly-functioning magical item, though it could be easily removed with a casting of dispel magic.

Any affected book was unharmed by triggering the spell. Upon its closing, the effects were renewed as if trap spellbook had just been cast. The original caster would freely remove the runes at will.

Usage
This spell was commonly used by the Red Wizards of Thay.