A study was made of similarities and differences in parent-child interaction in two contexts: a book-reading activity and a home computer activity involving an alphabet program. A total of 20 children 3 years of age and their parents (10 children with mothers, 10 with fathers) were videotaped in two 12-minute sessions of each activity. A variety of verbal and behavioral measures revealed a number of differences in participants' interactions with the two media. Book reading elicited more verbalization overall and was more exclusively tutorial with respect to naming things. Computer interactions featured more comments about things, parental directives about how to operate the computer, and questions from the children. More similarities than differences were found in the behavior of mothers and fathers; however, mothers were remarkably consistent in their interaction across the two tasks and fathers were not. Discussion of findings focus on media effects, parental effects, and the relevance of findings for the design of computer prereading activities for children. (Author/RH)