Spellbooks, Spell Preparation, and Wizard Identity in One D&D

 One of the consistent patterns in the One D&D playtest is that spellcasters are all becoming prepared-spells classes.

In the current iteration of 5E, there's a mix - Artificers, Clerics, Druids, and Paladins all have full access to the entire class spell list and can pick any spells they want that they're able to cast from their list at the end of each long rest, up to a certain amount (I believe it's a number of distinct spells equal to their spellcasting modifier plus their level for Clerics and Druids and half their level for Artificers and Paladins). Meanwhile, Bards, Rangers, Sorcerers, and Warlocks (as well as 1/3 caster subclasses, the Eldritch Knight Fighter and Arcane Trickster Rogue) simply learn new spells as they hit certain levels, and can only swap one out when they level up, making these sort of long-term decisions (the Warlock Mystic Arcanum feature, which is their means of getting 6th-9th level spells, I think is technically stricter and doesn't let you swap them out at all, officially, though as a DM I'd absolutely allow one to switch it if the original choice isn't working out).

Wizards have a foot on either side of this line. While they don't have access to the entire Wizard spell list, they get a sort of mini-game that allows them to learn additional spells beyond the two free ones that they get each level (starting with six at level 1). This minigame is somewhat DM-dependent - it's up to the DM to see how much gold the party gets access to, and how frequently the Wizard can find old spellbooks or spell scrolls to add spells to their collection. A rather wizard-unfriendly campaign could see them only ever getting their two spells per level past 1, which would mean that by level 20, they would have only 44 spells (not counting cantrips). But a campaign where money is plentiful and there are free public wizard libraries in every town would allow a wizard to potentially have a full 519 spells (again, not counting cantrips).

Then, among the spells copied into that spellbook, they prepare spells the way that a Cleric or Druid would, choosing from among them each day. The Wizard has the largest spell list of all classes, but it's unlikely that they'll ever have all the spells on that list, given the cost, time, and rare opportunity required to copy each spell. (My Wizard has the Order of Scribes subclass, so the time issue is negligible - even a 9th level spell only takes 18 minutes to copy, compared to 18 hours for other Wizards.)

However, as we've seen in the One D&D playtest, every previewed spellcaster class instead gets to prepare spells after a long rest, choosing from their entire spell list (so far with restrictions based on schools of magic and one of three broad lists, though it sounds like future playtest content might still designate some iconic spells as being limited to individual classes, such as, likely, Chaos Bolt for Sorcerers).

This, then, raises the question: what does the Spellbook even do anymore?

Presumably, the Wizard will have unfettered access to the entire Arcane spell list. I don't know if Sorcerers or Warlocks will be restricted in their choice of spell schools. Warlocks, I could imagine, might not be able to get Evocation spells, given that things like Fireball are usually limited to certain Warlock subclasses. Sorcerers are tougher - I could imagine cutting Conjuration from them, given that they tend not to have as many summoning spells, but then they would also lose teleportation spells like Misty Step.

If Sorcerers get access to the whole Arcane spell list, but Wizards are still limited to picking only spells they've copied into their Spellbooks, it would have the ironic effect of sort of swapping the two classes' general role - in current 5E, Sorcerers tend to have to focus on simpler, often blastier spells, and are built to be really good at raining down magical damage on foes, while a Wizard has more of a broad spellcasting toolbox, where they can pick up useful odds and ends here and there.

If we assume that Sorcerers and Warlocks will follow the "prepare any spell your class can cast at this level" model we've seen with every other spellcaster in the playtest, I think that the functionality of the Spellbook will have to change.

But I don't think we should get rid of it. The Spellbook is so iconic to the Wizard that losing it would feel like really losing what makes the Wizard a Wizard. So, what then?

My first thought is that Wizards might be able to expand the number of prepared spells they have per day beyond what other classes can do. The Wizard's role, after all, is to be the one with a vast trove of arcane knowledge. I could see this taking two different forms:

The first is that adding a spell to your spellbook would essentially work like Domain or Oath Spells. You effectively always have that spell prepared, and it doesn't count against the spells you've prepared. Now, the challenge here is that, left as is, that would be crazy-powerful. If acquiring spells for your book happens as easily as it does in the current version of the game, you'd have over twice as many spells ready as a Cleric. To deal with that, first, you'd significantly reduce the number of spells that the player can put in their spellbook.

You can do this two ways. The first is simply removing the free spells you get when you start off at level 1 and the two you get each time you level up. Essentially, you're still preparing a bunch of spells each day (presumably using the new system where you get one spell of each level to prepare for each spell slot you have that can cast that spell, so two 1st level spells at 1st level, etc. - unless they mercifully change that back to the old formula I far prefer) but if you want to have these extra prepared spells, you've got to find them, and then spend the time and money to add them to your spellbook.

Alternatively, though, you could also build a system that works the same regardless of how much money, spell scrolls, and time your DM affords you, which would be that instead, you simply get to add a certain number of spells to your spellbook as you level up. This would, of course, remove the "Spell Pokémon" minigame element of the class (Gotta Catch 'em All!) but it would make this a predictable and fair system for all Wizards.

However, perhaps there's another use for the Spellbook.

Another option is that Spellbooks could be used to more easily swap out your prepared spells. Perhaps Wizards would be able to, over the course of a minute (perhaps a limited number of times per day,) swap out a prepared spell for something copied into their spellbook, letting the Wizard focus on their go-to spells, or perhaps "frequently useful but also frequently not useful spells" for what they put in their book. Having Knock in your spellbook will be great if you come across a locked door while wandering across the desert, but not having to have it prepared for the many days that the closest equivalent to a door you encounter is the sphincter of some Purple Worm is also great.

The purpose of the Spellbook in the current class design is to reflect the Wizard's role as a versatile spellcaster, so the massive upgrade to the versatility of other spellcasters makes it important to find a way for the Spellbook to do this job in the new environment.

Now, to be fair, for all we know Sorcerers and Warlocks will simply have to one-and-done learn spells still, and this is all moot. But given how consistent the changes have been to spellcasters (and a change that I like, because I'm generally in favor of changes that make it harder for a player to "screw up" their character because of a poor or inappropriate build choice) I can only assume that we'll be seeing Sorcerers and Warlocks get the same treatment.