Some people use dream books as road maps to the dream world. Some of these maps are better than others. There are many destinations in the land of dreams. The map you use has a lot to do with where you end up. By writing down your dreams, you begin to create your own map of the dream world.
Some people use only one map for reality.
This is one of the physical world. They apply their beliefs to the formation of this map and as a navigational aide. They don't utilize maps of the dream world. They treat this inner world as somewhat of a mythical country. For many, practically all they know of this country is the nightmares they have had and that others have told them of, and because of this they have no desire to consciously travel there.