Invited Talks -- Nonmonotonic Description Logics – Requirements, Theory, and Implementations -- Our Quest for the Holy Grail of Agent Verification -- An Abstract Framework for Satisfiability Modulo Theories -- Research Papers -- Axiom Pinpointing in General Tableaux -- Proof Theory for First Order ?ukasiewicz Logic -- A Tableau Method for Public Announcement Logics -- Bounded Model Checking with Description Logic Reasoning -- Tableau Systems for Logics of Subinterval Structures over Dense Orderings -- A Cut-Free Sequent Calculus for Bi-intuitionistic Logic -- Tableaux with Dynamic Filtration for Layered Modal Logics -- The Neighbourhood of S0.9 and S1 -- EXPTIME Tableaux with Global Caching for Description Logics with Transitive Roles, Inverse Roles and Role Hierarchies -- Tree-Sequent Methods for Subintuitionistic Predicate Logics -- A Sequent Calculus for Bilattice-Based Logic and Its Many-Sorted Representation -- Updating Reduced Implicate Tries -- A Bottom-Up Approach to Clausal Tableaux -- Differential Dynamic Logic for Verifying Parametric Hybrid Systems -- System Descriptions -- Improvements to the Tableau Prover PITP -- KLMLean 2.0: A Theorem Prover for KLM Logics of Nonmonotonic Reasoning.