Research has long recognized the value of video technology in supporting preservice teachers' learning, and recent technological and conceptual advances further demonstrate its potential as an everyday tool for teacher education. This dissertation examines video's role in efforts to develop a "practice-based" curriculum for teacher education. Within a practice-focused theoretical framework (Reckwitz, 2002), this case study addresses features of the enacted curriculum that emerged as preservice teachers regularly shared and discussed videos of their teaching. The primary research question is: "What curriculum for teacher education can develop over time through instructional use of video records of preservice teachers' practice?" Data were collected in a master's level secondary teacher education program in which preservice teachers used video technology to record their teaching throughout the student teaching semester. The data included recordings of 16 discussions in which preservice teachers discussed their teaching videos with their peers, recordings of teacher educators' planning meetings, and documents related to the teacher education program and course. Through an activity theory lens, I examined the loose structure provided by the teacher educators' instructional model for video discussions and the ways participants developed this model within discussions. Through verbal analysis methods (Chi, 1997), I identified the discourse moves enacted by participants, the categories of content addressed, and the degree of alignment with the theoretical conception of teaching as a practice. The findings reveal a curriculum that emphasized the teacher's authority to act in ways that influence her students' classroom experiences--particularly their participation and engagement--while accounting for the nuances of particular teaching contexts. The enacted curriculum was characterized by preservice teachers' collective engagement in clinical reasoning and the interplay of evidence from both the video and their experiences, within an instructional setting characterized by a "culture of nice." The findings illustrate the promise and challenge of using videos of preservice teachers' teaching as a practice-based approach to teacher education; the dissertation addresses implications at the teacher education program level and for the larger project of developing curriculum for practice-based teacher education. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]