A theoretical framework of written language use and development that emerged from a two-year case study of one child's writing at home and in school during kindergarten and first grade is presented. First, the paper describes three elements which are found throughout the framework: the social web of experience, writing as relationships, and writers' agendas. Second, the paper presents the theoretical framework which consists of three basic parts: determinants, components, and themes of written language. Third, the paper discusses written language activity within the theoretical framework. Fourth, the paper examines writers' experience in the light of this theoretical framework. The paper concludes with a brief discussion of some implications of a theoretical framework of this nature. Six figures representing various aspects of the framework and one table presenting a summary of the thematic analysis showing differences between home and school writing of the young first-grade writer are included; a list of 51 references is attached. (RS)