Ellibur's Tome of the Planes

Anyone studying the tome diligently may learn the skill Knowledge: The Planes at a rate of 1 rank per month, so long as they have skill ranks unused. The book's contents are neverending, as the knowledge within it is always changing to challenge the reader to learn more. Readers may also learn the languages of planar inhabitants including Abyssal, Celestial, Infernal, Auran, Ignan, Terran, and Aquan.

In addition, once they reach rank 3 in this skill, they may specialize, learning a specific knowledge skill for a single plane of existence. Any plane may be studied, from Mount Celestia to the void of the Quasielemental Plane of Vacuum to the Demiplane of Dread. Knowledge of a single plane is more detailed, but more perilous. Anyone studying a specific plane recieves a +2 bonus for specialization on knowledge checks for that plane and can learn the location of portals to and from that plane (DC 15) and what spell keys to use there (DC 20), but each time a new rank is gained in a given plane the student must pass a Will check or be bodily transported through the pages of the tome to a random location on that plane of existence, leaving the tome behind.

Ellibur's tome has other benefits, too. Any spell involving travel between planes may be learnt as though it were 1 level lower if the reader of the tome has 5 ranks in planar knowledge. If the key for a spell cannot be obtained, a reader with the tome can cast the spell as though it were 1 level higher to make it work without the spell key. If the reader knows the true name of a creature, or the name of a place or object on a plane, the reader may ask the book to reveal the subject's location, and a moving picture will appear showing the location in the book. Finally, any picture in the book may be turned into a portal to that plane if the reader can make a planar knowledge check (DC 25).