This casebook presents profiles of farms using anaerobic digesters for animal manures in the Great Lakes States: Illinois, Indiana, Iowa, Michigan, Minnesota, Ohio and Wisconsin. The purpose of this casebook is to provide a picture of the current state of on-farm anaerobic digester (AD) use in these states in the spring of 2002. The summary information provided in these profiles can help those considering using AD technologies to make informed choices and provide a general improvement in implementation efficiency and operator success. Furthermore, through sharing their experiences, these early adopters may help service providers better understand the needs of their customers, and aid the next wave of adopters in making a smooth transition to using biogas systems.