You have mastered a small handful of spells, and can prepare these spells without referencing your spellbooks at all.
Prerequisite: 1st-level wizard
Benefit: Each time you take this feat, choose a number of spells that you already know equal to your Intelligence modifier. From that point on, you can prepare these spells without referring to a spellbook.
Normal: Without this feat, you must use a spellbook to prepare all your spells, except read magic.
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.
Pathfinder RPG Core Rulebook. Copyright 2009, Paizo Publishing, LLC; Author: Jason Bulmahn, based on material by Jonathan Tweet, Monte Cook, and Skip Williams.