Paraconsistent logic is a theory of reasoning in philosophy that studies inconsistent data. The discipline has several different schools of thought, including preservationism, which responds to the problems that arise when human beings continue to reason when faced with inconsistent data. On Preserving is the first complete account of the Preservationist School, which developed in Canada out of the early work of Raymond Jennings, Peter Schotch, and their students. Assembling the previously scattered works of the Preservationist School, this collection contains all of the most significant works on the basic theory of the preservationist approach to paraconsistent logic. With essays both written and rewritten specifically for this volume, the contributors cover topics that include the motivation for the preservationist approach, as well as more technical results of their research. Concise and unified, On Preserving is the ideal introduction to a distinct philosophical field.