I have a very simple question. What are all of the classes that have spell books? I want to know because as a magus any spell that I see in another spell book I can copy to my own spell book. I know that I probably don't understand that but if you want to tell me about that rule please answer my other question too. Thank you!
Sincerely,
Spencealot
Arcanist, magus, and wizard are the classes that come to mind.
Alchemist does not work because a Wizard cannot learn spells from an Alchemist's formula book -- and presumably, the same would apply to classes like the Arcanist and the Magus that are based on the Wizard.
But the three classes I listed above should all be able to use one another's spell books to learn new spells.
There may be some prestige classes with their own spellcasting progressions (not "+1 level of existing class") that also have a spellbook class feature, but I cannot think of them at the moment and do not feel up to checking through all of them.
Also note that the Magus spell list differs slightly from the Sorcerer/ Wizard spell list used by Wizards and Arcanists, so their spell books may contain spells that are difficult or impossible for a Magus to learn.