It's a story that has been told many times before in many variations. A human mathematics professor on earth has discovered a formula that the human race may not be ready for. At least that is what an alien race thinks, and the reason they decide to kill the professor and replace him with an alien duplicate. The alien must find anyone else who may have learned the formula and dispose of them. We can all guess that the the alien doppelganger will end up loving his new-found human family, and their dog... and peanut butter. Well, maybe I couldn't predict the peanut butter element, but this book serves to remind us of the qualities in our fragile and imperfect lives. We may not be ready for the bigtime, as far as superior alien races are concerned, but we have love.... and peanut butter.