This report of the Preschool Evaluation Project provides developmental profiles of handicapped children who attended preschool special education programs in Montgomery County Public Schools (Maryland), and estimates how effective these programs were in accelerating the development of children with various types of handicaps. The developmental skills of 646 children (aged 0-5) placed in special education were assessed at the time of placement and at the end of each school year, using the Battelle Developmental Inventory. Five major handicap groups were analyzed separately, including: language impairments, multiple handicaps, speech impairments, hearing impairments, and vision impairments. Results showed significant benefits to children receiving preschool special education services. Services appeared to produce greater benefits when they reached the children at younger ages, particularly for the multihandicapped. Parents' satisfaction with the preschool services was also assessed. Data are displayed on numerous figures and tables, and four appendixes explain the data collection procedures, present the study instruments, and provide an explanation of the value-added analysis technique used for this study. (JDD)