Artemidorus and the Oneirocritica
The First Dream Dicionary
The ancient Greek Artemidorus of Daldis was not a myth like the Oneiroi but an actual person. He lived in the second century CE and was one of the first serious writers on the meaning of dreams whose work has survived. His classic five volume work "Oneirocritica" is known as the original dream dictionary. You can buy the English translation under the title
Artemidorus considered dreams as falling into two distinct categories: those that reflected the dreamer's current situation (Enhypnia) and those that predicted the future (Oneiroi). He was especially interested in the latter and rejected Enhypnia as not worthy:
"People who live an upright, moral life do not have enhypnia or any other irrational fantasies, but rather oneiroi and generally ones that are directly predictive."
The interpretations of dreams by Artemidorus are subtle. A dream sign doesn't have one specific meaning - its meaning will vary from person to person, from culture to culture and from situation to situation. The symbolism needs to be interpreted in context. He summarised this in the well known line:
"the interpretation of dreams is nothing other than the juxtaposition of similarities"
It's interesting to note the commonality between some of today's modern psychological theories of dreams and the ideas of this ancient Greek scholar.