Preservice teachers enter formal studies of teaching with an array of personal history-based beliefs and about teaching, classrooms, and students. This report traces the interactions between preservice teachers' personal history-based lay knowledge and their decisions about the potential value of coursework-based principles of content area reading instruction. Preservice teachers countered professional, production arguments favoring direct instruction about reading processes with their own personal history-based practical arguments. Math and English majors rejected rationales for process-centered instruction for reading in each of their respective content areas and offered subject matter-specific defenses for traditional presentational formats. This document analyzes the quality and character of these arguments and proposes classroom strategies that teacher educators might use for gaining access to and a voice in preservice teachers' internal, decision-making dialogues. (Author)