This volume is one of several which describe the characteristics, quality, and costs of services to severely mentally retarded, severely emotionally disturbed, deaf-blind, and severely multiply handicapped clients aged 21 and under, in 100 providers across the nation. This volume presents the case studies organized according to the major handicapping conditions under study in the project. Providers were grouped for case study description according to whether they served a majority (75 percent or more) of severely mentally retarded, severely emotionally disturbed, deaf-blind, or severely multiply handicapped. A number of providers included in the study which do not serve a clear majority of children with one of these handicapping conditions were grouped together in the fifth and final case study. Each case study includes the following sections: summary; overview; characteristics of providers; observations of severely handicapped children and youth and the staff serving them; costs of provider services to severely handicapped children and youth; and quality of those services. Notable differences in day versus residential providers are described in the last paragraph of each section of the case studies. (RC)