This volume concerns the breakdown of dead organic materials by the basidiomycetes or toadstools, one of the three major groups of fungi. Although the decomposer members of this group are ecologically and commercially of immense importance, this is the first symposium to focus on them. Various aspects of the taxonomy, sporulation, growth, enzyme activity and genetics of the organisms are discussed first. The roles of basidiomycetes in the nutrient cycles and energy flow of terrestrial and aquatic habitats and their activities as aggressive rotters of trees, outdoor and indoor timber and plant litter and composts are described in the later chapters.