The material below is Open Game Content from a 3PP Source
Aura moderate transmutation; CL 7th
Slot none; Price 12,500 gp; Weight 1 lb.
This well-made tome is always of small size, typically no more than 12 inches tall, 8 inches wide, and 1 inch thick. All such books are durable, waterproof, bound with iron overlaid with silver, and locked.
A wizard can fill the 1,000 pages of a blessed book with spells without paying the material cost. This book is never found as randomly generated treasure with spells already inscribed in it.
Requirements Craft Wondrous Item, secret page; Cost 6,250 gp