Aristotle’s works on sleep and dreams provide striking examples of what Charles Kahn has called, in relation to the De anima, the Parva Naturalia and the zoological works as a whole, “the progressive character of the exposition” in Aristotle. Both on a macro-level and, as will be shown in this paper, within the confines of a more restricted investigation, Aristotle’s works on the soul and on living beings often display a careful structure, possibly motivated by didactic and/or rhetorical considerations, in which arguments and ideas gradually unfold in the course of a thought process that the reader is meant to go through. This thought process is informed by explanatory principles familiar from Aristotle’s psychology but also guided by expository techniques such as the dialectical reviewing of current opinions, the aporetic raising of puzzles, the gradual refinement of descriptions and definitions, and the use of repetition and cross-referencing. This paper aims to show that close analysis of the role of these expository principles in Aristotle’s discussion of sleep and dreams is illuminating not only for our appreciation of Aristotle as a writer, but also of crucial importance for the interpretation of specific passages that on the face of it seem to be in conflict with other passages or problematic in other respects. In particular, it will study the importance of the rhetorical principle of arrangement (taxis) in the exposition of Aristotle’s ideas as a means to enhance the persuasiveness of the views he wishes to put forward.