The most skillful interpreter of dreams is he who has the faculty of observing resemblances. Abraham Lincoln drempt of his own death. Condensation is two or more dream images forming a single image.
Dreams are very efficient.
According to Plato, Dreams came from the liver. Freud is the Father of Modern study of dreams, among other things. Muscles are paralyzed during REM sleep, to prevent you from acting out the dream images flitting through your mind. Lucid Dreaming is being conscious that you are dreaming. Egyptians created dream dictionaries.