Using a found spellbook as a Sorcerer-Wizard multiclass [duplicate]

Question

I have a Divine Soul Sorcerer 6 (with INT 13) playing in a published adventure.

I just found a spellbook with 11 spells in it of varying levels. All are wizard spells, and some of the spells are also on the sorcerer and cleric spell lists, to which I have access.

The specific spellbook can be found in this adventure and location:

Waterdeep: Dungeon of the Mad Mage, level 1, in the bugbear area.

The specific spells are:

1st level spells (x4): burning hands, comprehend languages, false life, sleep
2nd level spells (x3): darkvision, gust of wind, invisibility
3rd level spells (x2): dispel magic, lightning bolt
4th level spells (x1: blight

If I were to multiclass into Wizard, what do my options become for using this spellbook?

More precisely, if I were to take 1 level in Wizard, can I then cast the spells in this book, assuming of course I have the required spell slots/abilities from my Sorcerer levels?

Please note that my question is specifically regarding the found spellbook and how I can go about using it. This other question is not a duplicate because it is only talking about copying spells into another wizard's book. I'm looking for all options available to me to use the book and I'm not assuming copying is a requirement.

Answer 1

You must copy the spells from the found book into yours so you can use them

Per the Multiclass spellcasting rules:

You determine what spells you know and can prepare for each class individually, as if you were a single-classed member of that class.

You will still need to copy the spells from that spellbook into yours in order to be able to use them. Please see this question for more detail, but you'll need to spend the time and gold to move them into your spellbook in order to use them

That means that for the Wizard spells, you'll be a Level 1 Wizard. That gives you 3 Wizard cantrips and 6 spells in your newly gotten class spellbook.

At 1st level, you have a spellbook containing six 1st-level wizard spells of your choice. Your spellbook is the repository of the wizard spells you know, except your cantrips, which are fixed in your mind.

You'll be able to prepare 2 of the wizard spells in your spellbook (Level 1 wizard plus an INT modifier of +1.) These will be in addition to the spells you know as a Sorcerer.

Copying limitations - 1st level spells only

The rule around copying a spellbook still apply here (emphasis mine):

When you find a wizard spell of 1st level or higher, you can add it to your spellbook if it is of a spell level you can prepare and if you can spare the time to decipher and copy it.

Copying that spell into your spellbook involves reproducing the basic form of the spell, then deciphering the unique system of notation used by the wizard who wrote it. You must practice the spell until you understand the sounds or gestures required, then transcribe it into your spellbook using your own notation.

For each level of the spell, the process takes 2 hours and costs 50 gp. The cost represents material components you expend as you experiment with the spell to master it, as well as the fine inks you need to record it. Once you have spent this time and money, you can prepare the spell just like your other spells.

Because of the limitation that you can only copy a level of a spell you can prepare, you will only be able to copy level 1 spells from that book. But you can keep that book on hand if you continue to increase your wizard levels.

Spell Slots

Now, as as a Sorcerer 6/Wizard 1, you'll have the following spell slots from multiclassing:

• 4 1st level spell slots
• 3 2nd level spell slots
• 3 3rd level spell slots
• 1 4th level spell slot

This effectively lets you upcast your prepared 1st level wizard spells, but you still can only prepare 2 first level wizard spells.

You can cast either Wizard or Sorcerer spells with this (but use your ability modifier per class.) You'll also need a requisite component pouch or focus:

Each spell you know and prepare is associated with one of your classes, and you use the spellcasting ability of that class when you cast the spell. Similarly, a spellcasting focus, such as a holy symbol, can be used only for the spells from the class associated with that focus.

Ritual casting

Just a reminder that if you have any ritual spells in your spellbook, you can cast those as rituals without preparing them.

Answer 2

You Won't be Able To Use it Without Copying, With One Possible Exception

Generally Wizards have to copy spells they find to use them. Ergo, you can't directly use all the spells of a found spell book.

They also automatically get two spells in their book each level and start with six.

It is in that final point that you have a sliver of wiggle room. RAW says nothing about how your character gets the spellbook and the first six spells. All it says is that a spellbook is Wizard starting equipment and that:

At 1st level, you have a spellbook containing six 1st-level wizard spells of your choice.

A Wizard having a spellbook with six 1st level spells does not seem to be dependant on it being her starting class (and there would be some game balance issues if they didn't have them). You "have" the book, with the spells. There is nothing said about you having acquired your own blank spellbook and copied all these starting spells by your own blood, sweat, and toil (although this seems to be the heavily implied lore of the class).

Hence a strict RAW reading would seem to allow the use of a found spellbook with six 1st level spells. Rip some pages out.

Do note that, as pointed out to me in one of NautArch's comments it is supposed to be 1st level spells "of your choice" for the starting six, so unless the book has everything you would have chose anyway this becomes problematic in its own right.

It looks like there is not much 1st level choice in the spellbook. Still if you wanted to use even some part of the book for some portion of your six spells, the argument still applies for that. Rip everything else out, acquire free spells in another way (by explaination or out of thin air) until the total is six. Then you have to copy or level up.

There is some lore justification in terms of "I found this book and studied it" making more sense than "Bam! I'm part wizard now." It also seems like "I inherited my grandmother's book. All but six spells had crumbled to dust" would not be objectionable as character background fluff.

Now I would blame no one for not allowing this, nor do I propose that this is necessarily the best rule. But I don't think there is a strict RAW argument against it, and I do think not allowing it or some other means of starting into a wizard multiclass with 6 free spells is problematic.

Fundamentally I think it comes down to balancing the illogic of inexplicably getting spells the day you happen to multiclass wizard vs. the lore of how a wizard is supposed to get spells. You've got a mechanics v. lore v. fairness problem any way you slice it. Reasonable minds will differ. I would, however, note that the lore and spirit of Wizard spell acquisition is already a bit broken by the free spells on wizard level up, and that the lore of buying magic inks and materials is pretty flimsy.