Dreams can signify two different things: the kind that happen when we sleep and the kind that shape our future life-goals. First, a word about the sleep kind. They are the images, ideas and emotions that occur involuntarily in our minds during sleep. The content and purpose of dreams are not clearly understood, though throughout history they have been a topic of scientific speculation, as well as a subject of philosophical and religious interest. There is even a sixty-four thousand dollar word for the study of them: oneirology.