"Book of Spell" (魔ま導どう書しょMadōsho) is an archetype of Spell and Trap Cards that supports Spellcaster-Type monsters. The archetype, prior to "Return of the Duelist", had two cards that merely contained "Book of Spell" in their names. Also, "Book of Spell" cards from "Return of the Duelist" all share the restriction that only 1 copy can be activated per turn. This archetype is supported by the "Magical" series.

Most of the cards in this archetype are Spell Cards. The exception is "Hidden Book of Spell". As such, numerous support cards like "Necro Book of Spell" cannot use it for their effects nor can they help you get or use "Hidden Book of Spell". "Magical" cards usually specify a "Book of Spell" Spell Card in which it is also excluded. However "Grim Book of Spell" is an exception as it does not specify a Spell card specifically so it can still search it out.

Due to these cards searching each other out, they can be useful in Deck Thinning. Additionally, due to their effects benefiting Spellcaster-Type monsters, these cards can easily be used in a Spell Counter-based Deck for massive amounts of Spell Counters to be created. "Hidden Book of Spell" can be used in this case to recycle those cards for future use.

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