The Worshipful and Ancient Law of Gallifrey

The Worshipful and Ancient Law of Gallifrey (also called The Book of Rassilon) was a book that was once stored in the Panopticon Archive on Gallifrey. One of the Artefacts of Rassilon, it was also the "key" to Shada, the Time Lords' prison planet. When the pages were turned inside a TARDIS, it would take the craft to Shada.

The text of the book was written in ancient Gallifreyan and read largely as gibberish, though the book itself had several remarkable features, such as absorbing radiation, having no discernible atomic structure, time running backwards over it, being impervious to damage or even spectrographic analysis. The book had the power to absorb radiation and energy and feed it back, causing damage to the equipment studying it. (TV: Shada, WC: Shada, PROSE: Shada)

Removal from Gallifrey and subsequent use
While studying at the Time Lord Academy, the Master schemed to obtain the book from the Panopticon Archives, believing it held the key to ultimate power. He manipulated one of his Professors, Salyavin, and, when things went awry, framed Salyavin for the attempted theft. Realising he would be imprisoned whether guilty or innocent, Salyavin ironically decided to actually steal the book for himself before he was arrested, (PROSE: The Legacy of Gallifrey) left a decoy in its place — really a copy of a human work of fiction, entitled The Hitchhiker's…, in red binding copied on the Artefact's. (PROSE: Shada) Chronotis would later describe his crime in bringing such a dangerous book to Earth an argument, an oversight — but only inasmuch as he had "overlooked the fact that he had decided to take it". (TV: Shada)

After escaping from Shada, Salyavin, in his new identity as Chronotis, decided to take the book with him to Earth when he officially retired; he knew it was the only remaining way for other Time Lords to get back to Shada now that he had erased all knowledge of it from their minds so as to hide his jailbreak. Upon leaving, Chronotis thus packed up the book and left a decoy in its place — really a copy of a human work of fiction, entitled The Hitchhiker's…, in red binding copied on the Artefact's. (PROSE: Shada) Chronotis would later describe his crime in bringing such a dangerous book to Earth an argument, an oversight — but only inasmuch as he had "overlooked the fact that he had decided to take it". (TV: Shada)

Several years later, a remorseful Chronotis subsequently requested that the Fourth Doctor return it to Gallifrey for him. Following this meeting it was stolen by Skagra, who used it and the Doctor's TARDIS to travel to Shada. (TV: Shada, WC: Shada)

The Fourth Doctor later borrowed the book from Chronotis to access Shada once again and destroy the Krikkitmen stored there. (PROSE: Doctor Who and the Krikkitmen)

Once, the Doctor used a copy of the book to imprison a malevolent psychic entity known as the Garvond. Having done this, he dumped the copy in a dimensional fissure. (PROSE: The Dimension Riders)

A Venerada e Antiga Lei de Gallifrey