“Q: Is it a good thing to cultivate dreaming?
A: It is by cultivating the power of what is called “dreaming” that clairvoyance is developed.
Q: Are there many means of interpreting dreams – for instance, the interpretations given in dream-books?
A: None but the clairvoyant faculty and the spiritual intuition of the “interpreter”. Every dreaming Ego differs from every other, as our physical bodies do. If everything in the universe has seven keys to its symbolism on the physical plane, how many keys may it not have on higher planes?
Q: Is there any way in which dreams may be classified?
A: We may roughly divide dreams also into seven classes, and subdivide these in turn. Thus, we would divide them into:
1. Prophetic dreams. These are impressed on our memory by the Higher Self, and are generally plain and clear: either a voice heard or the coming event foreseen.
2. Allegorical dreams, or hazy glimpses of realities caught by the brain and distorted by our fancy. These are generally only half true.
3. Dreams sent by adepts, good or bad, by mesmerizers, or by the thoughts of very powerful minds bent on making us do their will.
4. Retrospective; dreams of events belonging to past incarnations.
5. Warning dreams for others who are unable to be impressed themselves.
6. Confused dreams, the causes of which have been discussed above.
7. Dreams which are mere fancies and chaotic pictures, owing to digestion, some mental trouble, or such-like external case.”
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 