About a billion years ago, give or take 500 million years [3], a population of aquatic, unicellular eukaryotes making sporangia containing zoospores each with a single posterior flagellum split into two lineages: one eventually gave rise to animals, the other to fungi. Here we shall summarize the major diversifications of the Fungi by introducing each major fungal branch in the order that it is thought to have diverged (Figure 1) and presenting salient facts about fungal modes of nutrition, reproduction, communication and interaction with other life. Our views are strongly influenced by the Fungal Tree of Life Project 4, 5 and 6. Readers interested in learning more about fungi are encouraged to consult any of a number of comprehensive texts 7 and 8.