Research in Palo Alto, California, is attempting to discover distinguishing characteristics of educationally handicapped children (EH) and to clarify the causes of their learning disabilities. 76 EH children and their 76 same sex siblings (EH sibs) were matched with 76 academically successful students (SA) and their same siblings (SA sibs). Matching was done on the basis of grade, sex, and intelligence for EH and SA; of grade and sex for the siblings. No significant differences were found between the experimental and control group in distribution of older and younger siblings, ordinal position in the family, socio-economic status, or fathers' occupations. Parental interviews, reading tests and academic histories of parents; psychological, educational, medical, and neurological evaluations of the children, and behavior ratings of the children were used. Examiners were unaware of the classification of the child as EH or SA. Preliminary findings include: (1) significant differences in favor of EH on the Performance Scale of the Wechsler Intelligence Scale for Children, (2) impaired ability of EH and EH sibs in numerical computation, sequencing, and fine-perceptual-motor-hand-eye coordination and memory, and (3) lower achievement of EH in reading and spelling. Neurological impairment was significant in several areas for EH, and some medical-history facts were distinguishing. (AE)