The variety of the mycological world is far greater than most people imagine. Tens of thousands of fungal species have been described and many more are known only from the abundance of their genes in soil and water. Fungi are hugely important as agents of wood decay in forests, and, as parasites, they have caused the deaths of millions of people by ravaging crops and reshaping natural ecosystems. Fungi perform a variety of essential functions in ecosystems, and are important to both agriculture and biotechnology. Their importance is now becoming better appreciated among scientists, though there is much still to be understood concerning their taxonomy and evolution. This Very Short Introduction highlights the variety and extraordinary natures of fungi, revealing the remarkable facts of fungal biology and the global significance of these enchanting organisms. ABOUT THE SERIES: The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area. These pocket-sized books are the perfect way to get ahead in a new subject quickly. Our expert authors combine facts, analysis, perspective, new ideas, and enthusiasm to make interesting and challenging topics highly readable.