Program Verification: to Err is Human -- Fond (and Frank) Memories of Frank -- Warmest Congratulations, Frank -- Conformance Checking of Real-Time Models: Symbolic Execution vs. Bounded Model Checking -- Resource Analysis of Distributed Systems -- Comparing Trace Expressions and Linear Temporal Logic for Runtime Verification -- Proper Protocol -- A Compositional Approach to the Verification of Hybrid Systems -- Array Abstraction with Symbolic Pivots -- Modeling Role-Based Systems with Exogenous Coordination -- Vats: A Safe, Reactive Storage Abstraction -- Denotational and Operational Preciseness of Subtyping: A Roadmap -- A Sound and Complete Hoare Logic for Dynamically-Typed, Object-Oriented Programs -- Self-Reconfiguring Microservices -- Statically and Dynamically Verifiable SLA metrics -- Effectively Eliminating Auxiliaries -- Towards a Proof Method for Paradigm -- Toward a Formal Foundation for Time Travel in Stories and Games -- Industrial Application of Formal Models Generated from Domain SpecificLanguages -- Formal Verification of Open Normative Multi-Agent System -- Moessner's Theorem: An Exercise in Coinductive Reasoning in Coq -- Towards a Kool Future -- On the Expressiveness of Synchronization in Component Deployment -- Characterisation of Simulation by Probabilistic Testing -- On Time Actors -- A Small-Step Semantics of a Concurrent Calculus with Goroutines and Deferred Functions -- Quicksort Revisited - Verifying Alternative Versions of Quicksort.

This Festschrift volume has been published in honor of Frank de Boer, on the occasion of his 60th birthday. Frank S. de Boer is a prominent member of the research community in formal methods and theoretical computer science. A brief look at his lengthy publication list reveals a broad area of interest and a versatile modus operandi with: logic and constraint programming; deductive proof systems, soundness, and completeness; semantics, compositionality, and full abstraction; process algebra and decidability; multithreading and actor-based concurrency; agent programming, ontologies, and modal logic; real-time systems, timed automata, and schedulability; enterprise architectures, choreography, and coordination; testing and runtime monitoring; and cloud computing and service-level agreements. For a while, he also liked failures, especially in semantics, and optimistically concluded with the failure of failures. In fact, Frank has an opportunistic approach to research. Rather than seeing obstacles, he finds opportunities.