The du Lac manuscript was one of the many tomes written by Josephus du Lac. It was kept in the Sunnydale High Library but it was stolen by Julia. The Manuscript was said to contain a number of dark rituals and spells. However, it was written in archaic latin so nobody but du Lac's followers could read it. Spike required this to perform a ritual that would make Drusilla well again. He hired a vampire to translate it 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 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.