Invited Presentations -- Functorial Boxes in String Diagrams -- Some Results on a Game-Semantic Approach to Verifying Finitely-Presentable Infinite Structures (Extended Abstract) -- Automata and Logics for Words and Trees over an Infinite Alphabet -- Nonmonotonic Logics and Their Algebraic Foundations -- Contributions -- Semi-continuous Sized Types and Termination -- Visibly Pushdown Automata: From Language Equivalence to Simulation and Bisimulation -- A Finite Semantics of Simply-Typed Lambda Terms for Infinite Runs of Automata -- The Power of Linear Functions -- Logical Omniscience Via Proof Complexity -- Verification of Ptime Reducibility for System F Terms Via Dual Light Affine Logic -- MSO Queries on Tree Decomposable Structures Are Computable with Linear Delay -- Abstracting Allocation -- Collapsibility in Infinite-Domain Quantified Constraint Satisfaction -- Towards an Implicit Characterization of NC k -- On Rational Trees -- Reasoning About States of Probabilistic Sequential Programs -- Concurrent Games with Tail Objectives -- Nash Equilibrium for Upward-Closed Objectives -- Algorithms for Omega-Regular Games with Imperfect Information -- Relating Two Standard Notions of Secrecy -- Jump from Parallel to Sequential Proofs: Multiplicatives -- First-Order Queries over One Unary Function -- Infinite State Model-Checking of Propositional Dynamic Logics -- Weak Bisimulation Approximants -- Complete Problems for Higher Order Logics -- Solving Games Without Determinization -- Game Quantification on Automatic Structures and Hierarchical Model Checking Games -- An Algebraic Point of View on the Crane Beach Property -- A Sequent Calculus for Type Theory -- Universality Results for Models in Locally Boolean Domains -- Universal Structures and the Logic of Forbidden Patterns -- On the Expressive Power of Graph Logic -- Hoare Logic in the Abstract -- Normalization of IZF with Replacement -- Acyclicity and Coherence in Multiplicative Exponential Linear Logic -- Church Synthesis Problem with Parameters -- Decidable Theories of the Ordering of Natural Numbers with Unary Predicates -- Separation Logic for Higher-Order Store -- Satisfiability and Finite Model Property for the Alternating-Time ?-Calculus -- Space-Efficient Computation by Interaction -- The Ackermann Award 2006.