Welcome! I amLoading... to unlimited status, and the return to full power for the archetype as a whole, I present to you the In-Depth Guide to playing Spellbook and its variants in Master Duel. Enjoy!
What is Spellbook?
“Spellbook” is an archetype of mostly Spells created to support the "Prophecy" monsters and to act as general Spellcaster support. Players who were playing Yu-Gi-Oh! back in 2013/2014 should know all about this archetype, because it was one of two viable decks back then, creating a double Tier 1 meta with Dragon Rulers until all of the Dragon Rulers and Loading... got banned. For newer players who are not familiar, a similar comparison to this is how the "Branded" Spells and Traps support the "Despia" monsters and act as general fusion support. The difference between Spellbook and Branded is that Spellbook is 10 years old, and Konami didn't exactly make the archetype with the meta a decade later in mind. Therefore, almost all of the Prophecy monsters and quite a bit of Spellbook Spells have been completely outclassed by newer cards. Nevertheless, with the help of other newer archetypes and the unban of Loading... , Spellbook is back to full power, and it is very possible to use different variants to grind the ranked ladder in Master Duel to various Levels of success.
The Useful Cards
As mentioned above, almost all of the cards from the "Spellbook" and "Prophecy" archetypes are basically unplayably bad in today's meta, and there are a lot of them. There is really no reason to cover every single Spellbook and Prophecy card, so I will only talk about all the useful ones below. I trust that you can read their effects, so I will only mention any nuances they may have.
(Note: You can add not just Spells, but also monsters or Traps).
(Note: His effect can only be activated if he is Normal Summoned or flipped face-up, but it is not once per turn).
This card does nothing immediately after it is activated and resolves, but during the End Phase of the same turn, it calculates the number of Spell cards activated after this card resolves.
(Note 1: any Spell activation counts, not just Spellbook Spells).
(Note 2: Spells that are chained to the activation of this card do not count).
(Note 3: Spells your opponent activates do count).
Then, you can add Spellbook Spells from your deck to your hand up to the calculated number.
(Note 4: you can add Spells with the same name multiple times).
(Note 5: you can add less than that number).