This think and much repaired book has seen better days, yet the title “Wonderbook” can still be made out along its spine. The pages are all handwritten or hand drawn, and in a wide variety of styles, languages and materials, and occasionally new pages have been inserted, sometimes those are hand made as well.
The owner of the Wonderbook can create any magical effect by just writing it or drawing it on a blank page of the book, taking at least 1 round per level of the spell but called upon, it uses the owner’s level for caster level and their Charisma or Wisdom (whichever is higher) as the casting statistic, if they have an appropriate Craft or Perform skill they can add +1 to the DC or effective caster level of the spell for each five point they exceed a DC of 10 by.
However, the magic of the book is drawn from the user’s place in their reality, each time they cast a spell, they must make a Will save (DC 11 + twice the spell level), if they fail the save, they take a cumulative -1 to future saves against the Wonderbook, if they fail by 5 or more, they take 1 + spell level in statistic damage randomly distributed between Charisma, Intelligence and Wisdom, and if they fail by 10 or more, they are unmade from reality and are recreated as a character in the book (in their own hand whether writing or art).
Who or what created the Wonderbook and if there is more than one of them is unknown.