Spellbooks

Each spellbook, formula book, or prayer book is a unique reflection of the personality and capabilities of its creator. Many of these tomes contain more than just spells, such as notes on the caster’s other research, personal diaries, naturalist sketches, or even political treatises. Some contain preparation rituals, each of which grants a boon—or sometimes a hindrance—to spellcasters who use the book to prepare their spells.
Spellbooks are the battery from which many spellcasters draw their power each day, containing detailed notes on the casting of every spell they know. Any prepared spellcaster who uses a spellbook (or similar entity) must refer back to it in order to prepare their daily compliment of spells. This is usually accomplished through an hour of study, meditation, or prayer at the start of a day. Such preparation requires a fresh mind, body, and/or spirit, and thus can only be done after a character gets 8 hours of effective rest (or however many hours is necessary for a member of that character's race). At this point, the spellcaster can choose what spells they will memorize for the day.
A typical adventuring spellbook is compact (for a spellbook), measuring roughly 12 inches wide by 18 inches tall, 3 to 6 inches deep, and 3-10 lbs. They are typically made from fine materials (leather bindings, vellum pages), cost around 50gp, and contain 100 usable pages. While this is the norm, the intrinsic and personal value of a spellcaster's spellbook means they often create much more elaborate tomes, suiting the designs to fit their character, survive the ravages of their environment, or as an homage to the power within their pages. Characters are not limited to one spellbook, and in fact may find themselves needing several as their compliment of spells grows ever larger.

Adding Spells to a Spellbook

Characters gain opportunities to add spells to their spellbooks through various sources, covered in the Learning New Spells article. As part of learning a new spell, a character must transcribe that spell into their spellbook.
How much space a spell takes to fully transcribe depends on the level of the spell. Cantrips or Orisons take one page each, and all leveled spells take one page per Spell Level in a spellbook. A spellbook must have enough empty pages to add a spell to it, and pages cannot typically be added to a spellbook (though larger spellbooks with more pages can be purchased or made).
Transcribing a spell to a spellbook can be a costly affair as well. With the exception of new spells learned with each level up (which can be added to a spellbook at no monetary cost), any spell added bears a material cost, representing specialized inks that must be used for proper magical writings. The cost for a given spell level is given on the following table, or can be calculated as the spell's level squared times 10gp.
A spellcaster can copy any spell into their spellbook from another source (such as a scroll or other spellbook), or transcribe a spell they have just gained a new understanding of (either from leveling up or Spell Research). A spellcaster can transcribe any spell they currently have prepared into a spellbook from memory. Transcribing a spell from memory does not require a Spellcraft check like copying new spells do.
Copying a spell into a spellbook takes one hour per spell level (cantrips take 30 minutes). Like the spell's cost, this time need not be paid for spells obtained for free at each level (it is assumed this time is spent in small parts over the course of their previous level).

Spell Level	Writing Cost
0	5 gp
1	10 gp
2	40 gp
3	90 gp
4	160 gp
5	250 gp
6	360 gp
7	490 gp
8	640 gp
9	810 gp

Selling a Spellbook

Captured or no longer needed spellbooks have a gold value equal to 50gp plus the cost to transcribe all the spells within it. This can be calculated by adding up the number of spells of each level within the book, then multiplying that by the cost per level in the table above. As with most items, spellbooks can typically be sold for is half their base value.

Preparation Rituals

Some rare spellbooks contain magic that provides a unique boon (or penalty) to anyone who prepares spells out of them. Any character who prepares at least three spells (not including cantrips) from a spellbook with a preparation ritual gains the effect of that ritual. The boon lasts until its effect is spent (as specified by the boon description) or the character prepares spells again (at which time it can be reapplied by preparing three spells from the book). A character can only have the effects of one boon at a time, no matter how many spellbooks they prepare from, though penalties from detrimental preparation rituals do stack.

Transcribing Preparation Rituals

Like spells, preparation rituals can be copied into new spellbooks. To imbue a spellbook with a preparation ritual, you must have the Scribe Scroll feat, as well as a number of ranks in Spellcraft and a Caster Level each equal to twice the highest Spell Level in the original spellbook. You also must have scribed at least three spells from the original spellbook into the new spellbook, at least one of whichs must be of the highest Spell Level found in the original spellbook. You must prepare those three spells (or know them, if you cast spells spontaneously) and perform an 8-hour creation ritual that requires supplies costing half as much as the value of the preparation ritual. At the ritual’s end, attempt a Spellcraft check (DC = 10 + twice the highest Spell Level in the original spellbook). If you succeed, the new spellbook gains that preparation ritual. If you fail, the supplies are wasted to no effect. Formula book preparation rituals are similarly imbued, but use extracts rather than spells, and instead of Scribe Scroll, you must have Brew Potion. A spellbook can have multiple preparation rituals, but it must meet the requirements for each. This does not affect the number of preparation rituals from which a character can benefit.