A grounded, unromantic review of Nature-Inspired Cyber Security and Resiliency (IET, 2020). The book argues that we can borrow defence principles from biology (immune systems, swarms, self-healing) to build adaptive digital security. The idea is clever but mostly speculative. The theory works on paper; the engineering doesn’t. Nature may be elegant, but enterprise networks aren’t petri dishes. Useful metaphors, immature mechanisms: an interesting academic exercise, not an operational blueprint.