Typed Functional Programming -- Well-Typed Programs Can't Be Blamed -- Exploring the Design Space of Higher-Order Casts -- Practical Variable-Arity Polymorphism -- Resolving Inductive Definitions with Binders in Higher-Order Typed Functional Programming -- ETAPS Invited Talk -- Using Category Theory to Design Programming Languages -- Computational Effects -- Modular Monad Transformers -- Handlers of Algebraic Effects -- Types for Object-Oriented Languages -- Is Structural Subtyping Useful? An Empirical Study -- An Interval-Based Inference of Variant Parametric Types -- Existential Quantification for Variant Ownership -- Verification -- Formalising and Verifying Reference Attribute Grammars in Coq -- Verified, Executable Parsing -- An Efficient Algorithm for Solving the Dyck-CFL Reachability Problem on Trees -- Amortised Memory Analysis Using the Depth of Data Structures -- ESOP Invited Talk -- The Financial Crisis, a Lack of Contract Specification Tools: What Can Finance Learn from Programming Language Design? -- Security -- All Secrets Great and Small -- Type-Based Automated Verification of Authenticity in Cryptographic Protocols -- Concurrency -- A Theory of Non-monotone Memory (Or: Contexts for free) -- Abstraction for Concurrent Objects -- Minimization Algorithm for Symbolic Bisimilarity -- Service-Oriented Computing -- Conversation Types -- Abstract Processes in Orchestration Languages -- Global Principal Typing in Partially Commutative Asynchronous Sessions -- Tisa: A Language Design and Modular Verification Technique for Temporal Policies in Web Services -- Parallel and Concurrent Programming -- Automatic Parallelization with Separation Logic -- Deny-Guarantee Reasoning -- A Basis for Verifying Multi-threaded Programs -- SingleTrack: A Dynamic Determinism Checker for Multithreaded Programs.

This book constitutes the refereed proceedings of the 18th European Symposium on Programming, ESOP 2009, held in York, UK, in March 2009, as part of ETAPS 2009, the European Joint Conferences on Theory and Practice of Software. The 26 revised full papers presented together with two abstracts of invited talks were carefully reviewed and selected from 98 full paper submissions. The topics addressed are typed functional programming, computational effects, types for object-oriented languages, verification, security, concurrency, service-oriented computing, parallel and concurrent programming.