Invited Tutorials -- Transactional Memory: Glimmer of a Theory -- Mixed-Signal System Verification: A High-Speed Link Example -- Modelling Epigenetic Information Maintenance: A Kappa Tutorial -- Component-Based Construction of Real-Time Systems in BIP -- Invited Talks -- Models and Proofs of Protocol Security: A Progress Report -- Predictability vs. Efficiency in the Multicore Era: Fight of Titans or Happy Ever after? -- SPEED: Symbolic Complexity Bound Analysis -- Regression Verification: Proving the Equivalence of Similar Programs -- Regular Papers -- Symbolic Counter Abstraction for Concurrent Software -- Priority Scheduling of Distributed Systems Based on Model Checking -- Explaining Counterexamples Using Causality -- Size-Change Termination, Monotonicity Constraints and Ranking Functions -- Linear Functional Fixed-points -- Better Quality in Synthesis through Quantitative Objectives -- Automatic Verification of Integer Array Programs -- Automated Analysis of Java Methods for Confidentiality -- Requirements Validation for Hybrid Systems -- Towards Performance Prediction of Compositional Models in Industrial GALS Designs -- Image Computation for Polynomial Dynamical Systems Using the Bernstein Expansion -- Cuts from Proofs: A Complete and Practical Technique for Solving Linear Inequalities over Integers -- Meta-analysis for Atomicity Violations under Nested Locking -- An Antichain Algorithm for LTL Realizability -- On Extending Bounded Proofs to Inductive Proofs -- Games through Nested Fixpoints -- Complete Instantiation for Quantified Formulas in Satisfiabiliby Modulo Theories -- Software Transactional Memory on Relaxed Memory Models -- Sliding Window Abstraction for Infinite Markov Chains -- Centaur Technology Media Unit Verification -- Incremental Instance Generation in Local Reasoning -- Quantifier Elimination via Functional Composition -- Monotonic Partial Order Reduction: An Optimal Symbolic Partial Order Reduction Technique -- Replacing Testing with Formal Verification in Intel CoreTMi7 Processor Execution Engine Validation -- Generating and Analyzing Symbolic Traces of Simulink/Stateflow Models -- A Markov Chain Monte Carlo Sampler for Mixed Boolean/Integer Constraints -- Generalizing DPLL to Richer Logics -- Reducing Context-Bounded Concurrent Reachability to Sequential Reachability -- Intra-module Inference -- Static and Precise Detection of Concurrency Errors in Systems Code Using SMT Solvers -- Predecessor Sets of Dynamic Pushdown Networks with Tree-Regular Constraints -- Reachability Analysis of Hybrid Systems Using Support Functions -- Reducing Test Inputs Using Information Partitions -- On Using Floating-Point Computations to Help an Exact Linear Arithmetic Decision Procedure -- Cardinality Abstraction for Declarative Networking Applications -- Equivalence Checking of Static Affine Programs Using Widening to Handle Recurrences -- Tool Papers -- D-Finder: A Tool for Compositional Deadlock Detection and Verification -- HybridFluctuat: A Static Analyzer of Numerical Programswithin a Continuous Environment -- The Zonotope Abstract Domain Taylor1+ -- InvGen: An Efficient Invariant Generator -- INFAMY: An Infinite-State Markov Model Checker -- Browser-Based Enforcement of Interface Contracts in Web Applications with BeepBeep -- Homer: A Higher-Order Observational Equivalence Model checkER -- Apron: A Library of Numerical Abstract Domains for Static Analysis -- Beaver: Engineering an Efficient SMT Solver for Bit-Vector Arithmetic -- CalFuzzer: An Extensible Active Testing Framework for Concurrent Programs -- MCMAS: A Model Checker for the Verification of Multi-Agent Systems -- TASS: Timing Analyzer of Scenario-Based Specifications -- Translation Validation: From Simulink to C -- VS3: SMT Solvers for Program Verification -- PAT: Towards Flexible Verification under Fairness -- A Concurrent Portfolio Approach to SMT Solving.

This book constitutes the refereed proceedings of the 21st International Conference on Computer Aided Verification, CAV 2009, held in Grenoble, France, in June/July 2009. The 36 revised full papers presented together with 16 tool papers and 4 invited talks and 4 invited tutorials were carefully reviewed and selected from 135 regular paper and 34 tool paper submissions. The papers are dedicated to the advancement of the theory and practice of computer-aided formal analysis methods for hardware and software systems; their scope ranges from theoretical results to concrete applications, with an emphasis on practical verification tools and the underlying algorithms and techniques.