Reasoning in form, Enrico Berti used to pledge, ought to be taught starting from adolescence. That each young adult be empowered to know that what s/he says is true ought to be considered as a human right. This book showcases two centuries of readings of Aristotle’s Organon, one of the greatest books of the Western philosophical tradition. This book is about nineteenth-century and twentieth-centuries readings of Aristotle’s Organon. The time span goes from Kant to Lukasiewicz. It is correctly old and new logic, which are divided by the threshold of the quantification of the predicate achieved in Boolean logic. An introduction and twelve well-argued chapters make the case for the choice of subject matter and periodization.