Can I copy prepared Cleric spells that are also on the Wizard spell list into my spellbook?

Question

I'm multiclassing as a Wizard2/Cleric3. I'm wondering if it's possible to prepare a spell from the cleric spell list and then if it's also found in the Wizard spell list, would I be able to write it down in my wizard spellbook?

I'm confused by this as the PHB states that if I find a scroll or a book, I can decipher it and boom, it's in my own book. I'm essentially my own walking book book. I've found this in the sidebar in the PHB under wizard regarding spellbooks.

Replacing the Book. You can copy a spell form your own spellbook into another book-for example, if you want too make a backup copy of your spellbook. This is just like copying a new spell into your spellbook, but faster and easier since you understand your own notation and already know how to cast the spell. You spend only 1 hour and 10gp for each level of the copied spell.

If you lose your spellbook, you can use the same procedure to transcribe the spells that you have prepared into a new spellbook. Filling out the remainder of yourspellbook requires you to find new spells to do so, as normal. For this reason, many wizards keep backup spellbooks in a safe place.

Now, lets say that I prepare Protection from Evil and Good, which is a 1st level spell and can both be found in the Cleric spells list and in the Wizard spell list. Shouldn't it be possible for me to write it down into my spellbook by following the given formula in the "Replacing the Book"; 10gp + 1hour for each level of the copied spell.

I understand that it would have been very different if the holder of the spell I want to copy is another creature (party member or not) but now it's all me. I know the spells, I own the book, I am the Wizard.

Answer 1

No you cannot transfer spells prepared as a Cleric into your spellbook

Just above the text that you reference, the sidebar in the PHB explains

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

The fact that the book explicitly says that it contains wizard spells is the killer here. Spells that you prepare as a cleric are not wizard spells. They are cleric spells, even if they are on the same spell list.

We know this because of the rules for multiclass spellcasters (PHB pg. 164)

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.

From this, we establish that your prepared spells as a cleric are "Cleric Spells" in that they are prepared as a cleric, and cast as a cleric; not as a wizard. And your prepared spells from your spellbook are "wizard spells" for a similar reason. Even if the two appear on the same spell list, each spell you have prepared is associated only with one of your classes.

The PHB then goes onto explain that when copying spells from spellbook to spellbook:

This is just like copying a new spell into your spellbook, but faster and easier, since you understand your own notation and already know how to cast the spell.

If copying from book to book is the same as adding new spells except faster, then we know that you can only transfer over wizard spells since you can only copy new wizard spells into the spellbook.

Finally, As you have pointed out:

you can use the same procedure to transcribe the spells that you have prepared into a new spellbook

The procedure in question is the same as copying over a new spell, or a spell from one book to another. Both of these processes require wizard spells to work. Thus, even though copying a spell down from memory doesn't specifically add any new restriction, it doesn't explicitly lift the general limitation on the procedure; the precondition that the spell in question is a wizard spell.

Answer 2

Not Directly

Knowledge, preparation, and spell casting ability are called out in the paragraphs that describe each Spellcasting class feature. Knowing, preparing, and casting are three different parts of the system, and have different rules binding them.

There would be no need to call it out if you could ignore the difference. It is especially important when multi-classing, because that's the way you get access to more than one set of spells - each Spellcasting class is considered separately for everything except slots (and Pact Magic classes are even separate for slots).

For the Cleric, Preparing and Casting Spells (PHB p58) explicitly refers to "cleric spells".

For the Wizard, Preparing and Casting Spells (PHB p114) explicitly refers to "wizard spells". The Your Spellbook sidebar also refers to "wizard spells".

In Multiclassing (PHB p164) it specifically addresses Spells Known and Prepared:

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 may have a common pool of slots for casting, but there is no crossover between the two different types of spells for knowing or preparing. When putting spells into your replacement wizard spell book, you can only select from those you have prepared as wizard spells.

It's worth noting that you do not have to split your prepared spells between the two classes. Each of them determines prepared spells individually, based on the individual class level and the individual class' spellcasting attribute.

Make a Scroll

It's not without cost (time and money), but Xanathar's Guide to Everything provides rules for Scribing a Spell Scroll. Once the character has a scroll of a spell that exists on both lists, the character could use that scroll to add it to their wizard's spellbook. Just be sure to pay attention to the rules in the Dungeon Master's Guide for copying a scroll into a spellbook; there's a chance of wrecking the scroll. Of course, the character can just make a new one and try again.

Answer 3

Yes, you can write a prepared spell on the Wizard Spell List into your spellbook as described in the Replacing the Book section of the Wizard class, regardless of what class you use to prepare the spell.

Per the description you have provided, with my own emphasis,

Replacing the Book. You can copy a spell form your own spellbook into another book-for example, if you want too make a backup copy of your spellbook. This is just like copying a new spell into your spellbook, but faster and easier since you understand your own notation and already know how to cast the spell. You spend only 1 hour and 10gp for each level of the copied spell.

If you lose your spellbook, you can use the same procedure to transcribe the spells that you have prepared into a new spellbook. Filling out the remainder of your spellbook requires you to find new spells to do so, as normal. For this reason, many wizards keep backup spellbooks in a safe place.

There is no restrictions on which class you have prepared the spell from.

If your DM is particularly strict with the rules, you may get caught on "If you lose your spellbook" and "into a new spellbook". Those are easy to get around, though, by having a party member hide your current spellbook, and then copying the spells into a new spellbook, which could become your backup. You then could copy the spell from the new spellbook into your main spellbook once your party member has given it back to you.

Since this answer seems controversial, I'll try another approach to copying prepared spells from the Cleric class that are also on the Wizard's spell list (an important distinction, since a Wizard can't copy or cast a spell such as Cure Wounds) into the Wizard's spellbook. I'm finding a shockingly small amount of material about this, but let's examine copying spell scrolls.

Per Spell Scroll in the DMG (page 200),

If the spell is on your class's spell list, you can use an action to read the scroll and cast its spell without having to provide any of the spell's components. Otherwise, the scroll is unintelligible.

This would mean that, as a Cleric, you would be able to craft a spell scroll of a spell that is on the Cleric's spell list and the Wizard's spell list. As a Wizard, since this spell is on the Wizard's spell list, you would then be able to copy the spell into your spellbook. I can't tell if your familiarity with your own notation and ability to already cast the spell would allow you to follow the cheaper copying conditions from the Replacing the Book section, or if copying from a scroll and not your own spellbook overrides that ability and forces you to follow the price and time as described in the Copying a Spell into the Book section. Since Cleric spells are Wisdom-based and Wizard spells are Intelligence-based, more DMs may be inclined to follow the more expensive rules, assuming they allow PCs to craft spell scrolls at all.

Per Copying a Spell into the Book of the 53 PHB (page 114), 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 level for which you have spell slots and if you can spare the time to decipher and copy it. Copying a 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.

The only downside to this tactic is, as is emphasized in the section above, there is an assumption that a Wizard wrote the spell that is being copied. This may just be fluff, though, as using a scroll is not held to any standard of who wrote it, and as such different classes have the ability to use the same spell scrolls if the spells are on both spell lists. So, again, more stringent DMs may not allow this.

However, in practice, creating a spell scroll and then immediately copying what you just wrote into your spellbook seems silly, since you could have just written what you copied to begin with.

Here are some somewhat-related questions I found:

• Who can create copies of spells that can subsequently be copied into spellbooks, etc?

• Can Wizards, Tome Warlocks, and those with the Ritual Caster feat use spells from each other's books?

• Is there a difference between “spell scrolls” and “spells on a scroll” for copying purposes?

• Can clerics use spell scrolls for spells they receive through their Divine domains?