The most convenient method in which we can arrange the various branches of our subject will perhaps be the following: first, to consider rather carefully the mechanism — physical, etheric and astral — by means of which impressions are conveyed to our consciousness; secondly, to see how the consciousness in its turn affects and uses this mechanism; thirdly, to note the condition both of the consciousness and its mechanism during sleep; and fourthly, to enquire how the various kinds of dreams which men experience are thereby produced. Chapter 1: Introductory
— CHARLES WEBSTER LEADBEATER