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.