The forest floor is running a computation that began 450 million years ago. We are only now learning to read it.
Beneath every forest, meadow, and farm on Earth, a network of fungal threads spans the soil with a density that exceeds human imagination: a single kilogram of forest soil contains more total fungal hypha length than the distance from London to Edinburgh. These threads, called hyphae, connect the roots of trees, transmit chemical alarm signals between plants under attack, redistribute carbon from productive to vulnerable parts of the ecosystem, and solve transport optimization problems that are formally equivalent to problems that computer scientists have been unable to solve efficiently since the 1970s.
This is the mycelium. And this book argues, with the rigorous attention to evidence that the claim requires, that it is processing information in a way that can be formally described as binary.
Mycelium Internet is the first comprehensive scientific account of fungal information processing written for a scientifically literate general audience. Drawing on foundational research from Suzanne Simard's landmark 1997 Nature paper on carbon transfer through mycorrhizal networks, Andrew Adamatzky's 2022 Royal Society characterization of electrical spike trains in the ghost fungus, Toshiyuki Nakagaki's Nobel-quality demonstration that Physarum polycephalum solves maze problems through physical computation, and the small-world network analysis of Boddy, Fricker, and colleagues that revealed the topology of mycelial networks to be formally analogous to the internet and the brain, Prof. Arenvix Caldoray builds the most complete case yet made that fungal networks are genuine information-processing systems.
The book covers the full scope of the evidence: the electrical signaling dynamics of individual hyphae; the spike-train statistics of mycelial electrical activity recorded over 2,000 hours of continuous monitoring; the mutual information between mycelial network states and environmental variables; the small-world and scale-free network architectures that make mycelia computationally powerful; the Pareto-optimal transport networks that mycelia build without any centralized control; the systemic acquired resistance signals that propagate through mycorrhizal networks to warn neighboring plants of pathogen attack; and the epigenetic memory mechanisms that allow mycelia to store information about past environmental conditions across generations.
It also covers the limits of the evidence, with a candor that distinguishes rigorous science writing from enthusiastic science popularization. Not all the claims made in popular accounts of the Wood Wide Web are supported by the current data. The distinction between material transfer and information transfer is real and important. The source-sink dynamics that drive mycorrhizal carbon flow may not require network-level decision-making. Prof. Caldoray makes these distinctions clearly and draws the conclusions that the evidence, rather than the enthusiasm, supports.
The result is a book that is both more exciting and more honest than the popular accounts that preceded it, because the actual scientific story, when told with precision, is more surprising, more significant, and more beautiful than any oversimplification.
The mycelium has been running since the Devonian. The computation has been running since before there were forests to network. Understanding it is not an optional intellectual luxury. It is essential for anyone who wants to understand how life works, why ecosystems function, and what we are standing on.
Essential reading for anyone fascinated by Entangled Life by Merlin Sheldrake, The Hidden Life of Trees by Peter Wohlleben, and Other Minds by Peter Godfrey-Smith.
