The aspergilli are a fascinating group of fungi exhibiting immense ecological and metabolic diversity. These include notorious pathogens such as Aspergillus flavus, which produces aflatoxin, one of the most potent, naturally occurring, compounds known to man. Conversely, also included are other fungi, such as A. oryzae, involved in the industrial production of soy sauce and sake, or A. niger, used for the production of citric acid and enzymes, such as glucose oxidase and lysozyme. Such is the interest in Aspergillus that, to date, the sequences of fifteen different Aspergillus genomes have been determined, providing scientists with an exciting resource to improve the understanding of Aspergillus molecular genomics and acting as a spring board for mining for new metabolites and novel genes of industrial or medical importance. In this book, leading Aspergillus researchers review and summarize the most important aspects of Aspergillus molecular biology and genomics. The book opens with a fascinating overview of the genus Aspergillus. This is followed by in-depth reviews of: the Aspergillus molecular systematics * comparative genomics * bioinformatics and systems biology of Aspergillus * transcriptional regulation * genetics and genomics of sexual development of A. nidulans * genomics and secondary metabolism * ecology * development and gene regulation in A. flavus * functional systems biology * and novel industrial applications of A. oryzae genomics.