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
After having sat in the Panopticon's Archives for thousands of years, The Worshipful and Ancient Law of Gallifrey was removed from Gallifrey by Professor Chronotis when he retired to Earth; the reason for this was that Chronotis was really the notorious Time Lord criminal Salyavin, who had escaped from Shada and subsequently erased all memory of its existence from the minds of his fellow Gallifreyans. As an artefact that could have led a curious Time Lord back to Shada to realise Salyavin had escaped it, the book had been watched over by Chronotis all these years in his occupation as archivist.

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