Chapter five talked all about sleep and what happens in our unconsciousness. The most interesting part of the chapter to me was the part about dreams, because scientists still do not know why we dream. I personally never remember my dreams, so the topic is interesting. The chapter listed many reasons why we dream, such as processing emotions, going over memories, and learning how to do something, but I want to know how it is the process works. Freud's Theory of Dreams said that dreams change our feelings into symbols that we need to interpret. There are five stages of sleep that involve the body "powering down", to settling into a deeper sleep, to when the brain is the most active. Déjà vu was mentioned in the chapter, another topic I find interesting. Déjà vu is the feeling that something has happened before, though you know the experience is new. Jamais vu was also mentioned, which is the opposite. There are many sleep issues, such as sleep apnea, insomnia, sleepwalking, and night terrors. Drugs and substance abuse was a large part of the chapter. There are depressants, stimulants, narcotics, and psychedelics (or hallucinogenic). I think the whole topic of what happens in our unconscious state is something interesting to learn about and I hope there will be more research in the future about dreams.