Taking as its starting point a cogent analysis of the fundamental concepts of “legality” and the “rule of law,” Limiting Arbitrary Power undertakes a specific study of the contents of the vagueness doctrine. Dr. Ribeiro presents an in-depth exploration of the courts’ current approach, and suggests how it may be refined in the future. In that regard, he proposes techniques for legislative drafting in which certainty could be enhanced without compromising the flexibility required in law. Acknowledging that to date, the doctrine has yet to be been granted an autonomous status for invalidating legislation, he also examines in detail the possible situations in which vagueness may become applicable under the Charter.