In the past half century, filamentous fungi have grown in commercial importance not only in the food industry but also as sources of pharmaceutical agents for the treatment of infectious and metabolic diseases and of specialty proteins and enzymes used to process foods, fortify detergents, and perform biotransformations. The commercial impact of molds is also measured on a negative scale since some of these organisms are significant as pathogens of crop plants, agents of food spoilage, and sources of toxic and carcinogenic compounds. Recent advances in the molecular genetics of filamentous fungi are finding increased application in the pharmaceutical, agricultural, and enzyme industries, and this trend promises to continue as the genomics of fungi is explored and new techniques to speed genetic manipulation become available. This volume focuses on the filamentous fungi and highlights the advances of the past decade, both in methodology and in the understanding of genomic organization and regulation of gene and pathway expression.