Biologist and mycologist Merlin Sheldrake explores the strange and wonderful world of fungi in his book Entangled Life: How Fungi Make Our Worlds, Change Our Minds, and Shape Our Futures. It can be microscopic, but also forms the largest single organism in existence, covering 10 square kilometres and weighing 35,000 tons. It can turn insects into zombies and even displays qualities that seem to resemble intelligence, memory, and communication. In his book, Sheldrake suggests that the study of fungi can shed new light on the inter-connectedness of nature. He pays particular attention to underground fungal networks, the root system known as mycelia, which Sheldrake calls the tissue that holds together much of the world.