This study explores how public-school teachers who host student teachers in urban, grade 7-12 classrooms (referred to as cooperating teachers or classroom mentors in this study) define their role in preparing pre-service teachers. This study is particularly interested in yielding insight into how participants describe the "practice" of preparing teachers and how this compares with university-based notions of practice-based teacher education (Grossman, 2018). Through the use of qualitative methodologies this study will explore mentor interactions with their student teachers, as well as whether these interactions reshape their practice and classrooms. Additionally, this study will explore the extent to which mentor teachers' past experiences influence their mentoring practices as well as how university-provided guidance such as communications, handbooks, and professional development shape mentors' conceptions of what it means to be a teacher educator. Knowledge about how in-service teachers define themselves as teacher educators could provide valuable insight into how school districts can build structures for effective field-based teacher education and where they might engage Universities to fill gaps. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]