This book is a masterpiece in the subject of argumentation. Since Descartes the rethorical argumentation got a bad conotation, as a disguise to fold the truth. But, as Perelman brightly teachs, not all structures of the reality can be describe just by the formal (mathematical) logics. In fact, some "truths" can only be discovered by using argumentation, such as political or moral subjects. In a democratic scene, the awakening of a new logic is needed, because the mathematical method can not be aplied to all areas of thinking anymore.