Why do some people remember their dreams and others do not? Which brain region is the most important? Can I learn from a text by listening to it while I sleep?  Are there people or animals with more or fewer than two brain hemispheres? Can you unlearn sleeping in the dark? Do we really have a reptile brain, a mammal brain, and a human brain inside our heads? What is the purpose of brain research? Can I train plasticity? How are memories made in the brain? Why are you grumpy after a bad night of sleep?