The present book is the first monograph ever with a central focus on the proof theory of paraconsistent logics in the vicinity of the four-valued, constructive paraconsistent logic N4 by David Nelson. The volume brings together a number of papers the authors have written separately or jointly on various systems of inconsistency-tolerant logic. The material covers the structural proof theory of N4, its fragments, including first-degree entailment logic, related logics, such as trilattice logics, connexive systems, systems of symmetric and dual paraconsistent logic, and variations of...