Historically fungi included diverse organisms. In view of the recent developments in their ultra structure, biochemistry and molecular biology, the book provides a fresh look at the status of fungi in the biological world. Unlike traditional textbooks, taxonomic groups of fungi and related organisms studied by mycologists have been reshuffled and assigned positions according to modern scheme of classification. In the light of the advent of genetic manipulation and allied technology, the role of fungi in commercial production of unusual drugs, as hormones and some proteins, is examined. Some recently developed fungal products useful in agriculture, forestry and food industry are also briefly described. Besides students the book should also interest those inclined to learn what fungi do to mankind.