Doppelganger: A Tale from the Realm of the Blind

In the thirteenth book of the Realm of the Blind series, James Wendt meets a traveler from another Universe. In this other universe, Wendt disappeared due to the use of a form of PolyjuicePotion that completely and permanently changes one into a clone of the person whose DNA material was added to the potion.This traveler has accidentally arrived in Wendt's universe. She has his memories up to the use ofPolyjuice potion and her own afterwards. In Wendt she meets her predecessor.In the meantime an alien who wants to recreate the universe by sending it back to the Big Bang and starting over from scratch has started an interstellar war into which Wendt is drawn. Can he and his fellow Professors save the universe from the Big Crunch?