Black Scrolls of Rassilon

The  were a set of scrolls containing forbidden knowledge from the Dark Time. They were found by President Borusa within a casket marked with the Seal of Rassilon. To falsely implicate the Castellan in opening the Death Zone, Borusa left the casket and the scrolls (or convincing copies) in his chambers. Before anyone could examine the scrolls to confirm what they were, Borusa ensured that they spontaneously combusted.

According to the Fifth Doctor, the Black Scrolls were out of print by his time. (TV: The Five Doctors)
 * This implies there were multiple copies, although the Doctor may not have been serious.

The Master's TARDIS library contained the Black Scrolls, alongside other reviled works. (PROSE: The Quantum Archangel)

Behind the scenes
Pergaminhos Negros de Rassilon
 * The word The is indicated to be part of the title in The Quantum Archangel.