A process has been developed for the treatment of municipal solid waste to separate and recover the cellulosic biomass from the nonbiomass components. The process, known as steam classification, transforms the pulp and paper materials, food wastes, and soft yard wastes into a fairly uniform product that appears to be highly suitable as a feedstock for conversion to fuel, fertilizer, and/or fermentable sugars. The physical and chemical properties of this cellulosic feedstock have been determined. The material has also been tested as a feedstock for composting and for cellulytic enzyme hydrolysis to yield glucose.