Dr. Nancy Davidson is a psychologist whose book is titled "The Secret of Lost Cats: One Woman, 20 Posters, and a New Understanding of Love." Dr. Davidson, a cat owner and cat lover, lost her cat Zak and hung signs all around her neighborhood, in the hopes that someone could help bring him home - and she eventually did find him. She ultimately investigated the stories behind 20 other people who lost a cat and posted signs.