"With reference to viral infections," the Librarian says, "if I may make a fairly blunt, spontaneous cross-reference—something I am coded to do at opportune moments—you may wish to examine herpes simplex, a virus that takes up residence in the nervous system and never leaves. It is capable of carrying new genes into existing neurons and genetically reengineering them. Modern gene therapists use it for this purpose. Lagos thought that herpes simplex might be a modern, benign descendant of Asherah."