It is remarkable that a three-pound mass of gray matter creates the world around us, and the entire experience of consciousness for every human being. This accurate self-awareness is so critical to our identity as human. Chapter 5 in the Lilienfeld textbook is exclusively about consciousness. The chapter first discusses the most common break in consciousness, which is sleep. It then goes into what I find some of the most interesting topics of psychology, phenomena of alterations of consciousness and other unusual experiences.
The world around us always feels so permanent and sturdy. However, when one thinks of our surroundings as something created from signals being interpreted in the brain, it appear less stable. A small occurrence within the brain can cause people to see and hear things that aren't there. People go through strange events such as mystical and out-of-body experiences and déjà vu more frequently than most of us realize. People have even found ways to alter consciousness, whether it is through practices such as hypnosis or substances like drugs. The phenomenon of human awareness is something so important and so delicate, that it is fascinating to learn about how it can change, and what specifically happens within the brain that cause these things. Learning about the topics covered in this chapter shatter the definition of the world around as an unchanging place. This realization is oddly terrifying, and is probably part of the reason why I find it so interesting.
A depiction of brain activity during the most common altered state of consciousness, sleep (especially REM sleep). Photo from http://www.understandsleep.com/the-science-of-sleep/