This volume explores the cutting edge of computational paradigms inspired by natural systems. It presents the proceedings of the 21st International Conference on Unconventional Computation and Natural Computation, UCNC 2024, featuring 19 carefully reviewed papers selected from 27 submissions. The research spans a wide array of topics, including amorphous computing, cellular automata, chaos-based computing, and various forms of bio-inspired and quantum computing. These papers collectively advance the understanding and application of computation that mimics or draws from biological and physical processes.

This collection represents a snapshot of current research in unconventional and natural computation, as presented at a dedicated international conference. The selection of papers suggests a focus on theoretical advancements and novel algorithmic approaches derived from natural phenomena. The breadth of topics indicates a field that is actively exploring diverse computational models beyond traditional von Neumann architectures.