“Mushrooms are the fruiting bodies of fungi. Fungi are diverse and often flexible, and they live in many places, ranging from ocean currents to toenails. But many fungi live in the soil, where their thread-like filaments, called hyphae, spread into fans and tangle into cords through the dirt. If you could make the soil liquid and transparent and walk into the ground, you would find yourself surrounded by nets of fungal hyphae. Follow fungi into that underground city, and you will find the strange and varied pleasures of interspecies life.”