- “I'm guessing it wasn't a 'Taste of the Vatican' cookbook.”
- ―Buffy Summers[src]
Du Lac Manuscript was a book written by Josephus du Lac. It was said to contain a number of dark rituals and spells. However, it was written in archaic Latin, so nobody but his followers could read it.
In 1997, the Du Lac Manuscript was kept in the Sunnydale High School library, as part of Watcher and librarian Rupert Giles' personal collection. It was then stolen by the vampire Julia for Spike, who required it to perform a vampire restoration ritual that would make Drusilla well again. He forced his minion Dalton to translate the manuscript but concluded that it required the Du Lac cross to translate it.
The cross was buried in Du Lac's tomb; many vampires went to steal it, however Buffy Summers attempted to stop them, being in the end unsuccessful. The ritual required the sacrifice of Angel, because he was Drusilla's sire. Angel was saved by Buffy during the ritual. Even though it was said that Angel would have to be sacrificed in order for the ritual to work, he wasn't and the ritual worked to restore Drusilla's strength anyway.