World of Prophecy

The monster effect "When this card is Special Summoned by the effect of a Spellcaster-Type monster or a 'Spellbook' Spell Card: You can target 2 'Spellbook' Spell Cards in your Graveyard; add them to your hand. You cannot Special Summon other monsters during the turn you activate this effect" is a Trigger Effect. (It can be activated during the Damage Step.)

The monster effect "You can target 2 'Spellbook' Spell Cards in your Graveyard; add them to your hand" is an effect that targets 2 "Spellbook" Spell Cards in your Graveyard.

The monster effect "When you add cards to your hand with this effect: You can reveal 4 'Spellbook' Spell Cards with different names from your hand; destroy all other cards on the field" is a Trigger Effect. (It does not target.)

The monster effect "Destroy all other cards on the field" is an effect that can be activated optionally when you add cards to your hand by the monster effect of "Spellbook of Fate" (Note: Referring to "High Priestess of Prophecy" / "Temperance of Prophecy" context). (It can be activated during the Damage Step.)