Extracts - new wizard spells into extract list? For Alchemists

[Crexis]

Rules state: "Alchemists can learn new extracts in 2 ways, either as part of leveling up, or by learning from a scroll or wizard’s spellbook. To learn from a scroll or a spellbook an alchemist makes a simple DC 15+spell level spellcraft check and if he passes he can copy the spell to his formulabook. Grab formula whenever you get the chance, they are few and far between."

Does this mean if I look at one of our wizards (for example) scrolls or wizard book. I can do a spellcraft check and if I succeed and put into my formula book that I can use it as an extract? So basically I could maybe get access to any type of non-alchemist spell and use it as an extract?

[Grey_Mage]

No. It still has to be in your spell list
Like a wizard you can have unlimited spells (extracts) known that you can use to prepare your daily slots if you have unlimited resources to buy and document them.

This is also covered by the FAQ that states adding a spell to spells known doesn't allow an alternate class lacking that spell from using spell slots to cast it.

[thejeff]

I'm not sure which Rules you're quoting. The pfsrd entry says "An alchemist can also add formulae to his book just like a wizard adds spells to his spellbook, using the same costs and time requirements. An alchemist can study a wizard’s spellbook to learn any formula that is equivalent to a spell the spellbook contains."

Which is substantially equivalent to my copy of the APG.

The key is "any formula that is equivalent to a spell the spellbook contains". You can only learn formula that are on your formula list. You can learn them from a scroll or a wizard's spellbook, but they have to be spells that match alchemist formula already.

[Crexis]

As an alchemist I have a list of formula/extracts that I can use.

I believe I have access to all of them on the list.

Why do I need to use spellcraft? If I look at my wizards spellbook can I copy / craft one of the spells then use it as my own as an extract?

[thejeff]

Crexis wrote:

As an alchemist I have a list of formula/extracts that I can use.

I believe I have access to all of them on the list.

Why do I need to use spellcraft? If I look at my wizards spellbook can I copy / craft one of the spells then use it as my own as an extract?

It works basically like a wizard learning spells.

You get one free formula at every level to add to your formula book, in addition to the starting ones.
If you want formula beyond that, you need to learn them somewhere. You can learn them from other alchemist's formula books, scrolls or spellbooks. To do so, you need to make the spellcraft roll and spend the money to copy the formula - just as if you were a wizard adding the spell to your spellbook.
But you can only do that for spells that are also on the alchemist formula list.