For any character class who depends on a “Book” for daily memorization of spells or abilities abilities:
HOUSE RULE: There is no cost for your first spell book or to inscribe your spells into your primary spell book. For any extra (backup) books the character may inscribe see Table: Spell Level and Writing Costs below.
|Spellbook||15 gp||3 lbs.||100 pgs|
|Spellbook, compact||50 gp||1 lb.||70 pgs|
|Spellbook, traveling||10 gp||1 lb.||50 pgs|
Wizard Spells and Borrowed Spellbooks
A wizard can use a borrowed spellbook to prepare a spell he already knows and has recorded in his own spellbook, but preparation success is not assured. First, the wizard must decipher the writing in the book (see Arcane Magical Writings, above). Once a spell from another spellcaster’s book is deciphered, the reader must make a Spellcraft check (DC 15 + spell’s level) to prepare the spell. If the check succeeds, the wizard can prepare the spell. He must repeat the check to prepare the spell again, no matter how many times he has prepared it before. If the check fails, he cannot try to prepare the spell from the same source again until the next day. However, as explained above, he does not need to repeat a check to decipher the writing.
Adding Spells to a Wizard’s Spellbook
Wizards can add new spells to their spellbooks through several methods. A wizard can only learn new spells that belong to the wizard spell lists.
Spells Gained at a New Level
Wizards perform a certain amount of spell research between adventures. Each time a character attains a new wizard level, he gains two spells of his choice to add to his spellbook. The two free spells must be of spell levels he can cast.
Spells Copied from Another’s Spellbook or a Scroll
A wizard can also add a spell to his book whenever he encounters one on a magic scroll or in another wizard’s spellbook. No matter what the spell’s source, the wizard must first decipher the magical writing (see Arcane Magical Writings). Next, he must spend 1 hour studying the spell. At the end of the hour, he must make a Spellcraft check (DC 15 + spell’s level). A wizard who has specialized in a school of spells gains a +2 bonus on the Spellcraft check if the new spell is from his specialty school. If the check succeeds, the wizard understands the spell and can copy it into his spellbook (see Writing a New Spell into a Spellbook). The process leaves a spellbook that was copied from unharmed, but a spell successfully copied from a magic scroll disappears from the parchment.
If the check fails, the wizard cannot understand or copy the spell. He cannot attempt to learn or copy that spell again until one week has passed. If the spell was from a scroll, a failed Spellcraft check does not cause the spell to vanish.
In most cases, wizards charge a fee for the privilege of copying spells from their spellbooks. This fee is usually equal to half the cost to write the spell into a spellbook (see Writing a New Spell into a Spellbook). Rare and unique spells might cost significantly more.
A wizard can also research a spell independently, duplicating an existing spell or creating an entirely new one. The cost to research a new spell, and the time required, are left up to GM discretion, but it should probably take at least 1 week and cost at least 1,000 gp per level of the spell to be researched. This should also require a number of Spellcraft and Knowledge (arcana) checks.
Table: Spell Level and Writing Costs
Spell Level Writing Cost
Writing a New Spell into a Spellbook
Once a wizard understands a new spell, he can record it into his spellbook.
Time: The process takes 1 hour per spell level. Cantrips (0 levels spells) take 30 minutes to record.
Space in the Spellbook: A spell takes up one page of the spellbook per spell level. Even a 0-level spell (cantrip) takes one page. A spellbook has 100 pages.
HOUSE RULE: A wizard may only spend up to a maximum of ten (10) hours per day learning and copying spells.
HOUSE RULE: Only one (1) wizard at a time may use a given spellbook or scroll to learn and copy a spell.
Materials and Costs: The cost for writing a new spell into a spellbook depends on the level of the spell, as noted on Table: Spell Level and Writing Costs. Note that a wizard does not have to pay these costs in time or gold for spells he gains for free at each new level.
Replacing and Copying Spellbooks
A wizard can use the procedure for learning a spell to reconstruct a lost spellbook. If he already has a particular spell prepared, he can write it directly into a new book at the same cost required to write a spell into a spellbook. The process wipes the prepared spell from his mind, just as casting it would. If he does not have the spell prepared, he can prepare it from a borrowed spellbook and then write it into a new book.
Duplicating an existing spellbook uses the same procedure as replacing it, but the task is much easier. The time requirement is halved.
Selling a Spellbook
Captured spellbooks can be sold for an amount equal to half the cost of purchasing and inscribing the spells within.
Paizo Employee Pathfinder Design Team Official Rules Response Aug 1, 2013, 02:55 pm
Pathfinder Roleplaying Game Core Rulebook (OGL)
Preparing Spells in Open Slots: The Magic chapter says a wizard can leave spell slots open and prepare spells in them later. Can any other class do this?
That text was written when wizard was the only class that prepares arcane spells. This option is also available to magus and witch characters (both of which are classes that prepare arcane spells).