Opportunities for and limits upon diary writing in one second/third-grade classroom are examined with the purpose of stimulating critical thinking about two issues: (1) the diary's potential within the school writing curriculum, and (2) the classroom as an environment for the teaching and learning of writing. Field notes, teacher journal entries, and student diary entries demonstrate how diary time was started, modified, and sustained. The activity is analyzed in terms of teacher planning, implementation, audience, and the function of diary writing for young children. Conflicting messages regarding issues of privacy, correctness, and audience illustrate the complexity of carrying out this kind of writing occasion in an elementary school classroom and account for the eventual deletion of diary time from the schedule of classroom activities. (Author/RH)