This Festschrift is dedicated to Alan Mycroft who formally retired from the University of Cambridge after almost 40 years. Following a BA in Mathematics from the University of Cambridge in 1977, Alan took the Diploma in Computer Science in 1978. He then completed a PhD in Edinburgh in 1981 on Abstract Interpretation and Optimising Transformations for Applicative Programs under the supervision of Rod Burstall and Robin Milner. After an EPSRC postdoctoral fellowship at Edinburgh and a research assistant position at Chalmers University, he returned to the University of Cambridge in 1984 and remained there until his retirement in 2023. Alan is well-known for pioneering contributions to programming language theory and applications, covering both design and implementation. His work ranges from compilation and optimisation techniques, through semantics, static analysis, and type systems, to parallel, concurrent, and dataflow programming. He co-created the Norcroft C compiler with Arthur Norman, he co-authored the book Java 8 in Action: Lambdas, Streams, and Functional-Style Programming, and he co-founded the Raspberry Pi Foundation, a hugely successful initiative to develop programming skills and thinking for all ages. In addition to his excellent research profile, Alan has been an inspiring teacher, mentor, and collaborator, always generous with encouragement and feedback. The impact and scope of his career is reflected in the breadth of topics in this volume, a fitting tribute to him.