I was curious since there are newer class that use a Spell book or Formula Books would qualify for this feat?
Spell Mastery: Can an alchemist, magus, or witch select this feat?
As written, no, as the feat's prerequisite is "1st-level wizard."
However, the feat was written before the existence of the alchemist, magus, and witch classes, and it is a perfectly reasonable house rule to allow those classes to select the feat and apply its benefits to an alchemist's formula book, magus's spellbook, or witch's familiar.
That FAQ is from May 2013, so it doesn't list the even newer classes, but it clearly applies.
alright I figured it did. Just needed clearification
For those playing PFS, the PFS Campaign Clarifications now updates the language.
Core Rulebook
Page 134—Treat the prerequisite for the Spell Mastery feat as though it read "able to prepare 1st-level arcane spells or prepare 1st-level extracts." As appropriate, treat any wizard-specific language in the feat as though it referenced the equivalent language for any qualifying class (e.g. "formula book" or "familiar" instead of "spellbook" or "extract" instead of "spell").
So now I can finally make a Magus Maagambian Arcanist to use Shillelagh or Flame Blade
So now I can finally make a Magus Maagambian Arcanist to use Shillelagh or Flame Blade
Yes, that does seem possible now.