The proposed dissertation follows a three article format. The articles represent two distinct but interrelated strands of research; the first article examines the role of a cooperating teacher as an expert and co-learner. The second article is an exploratory case study examining the use of a structured mentoring guide, The Reflection and Engagement Guide (REG) to support the work of cooperating teachers. The third is a practitioner article for teacher educators and cooperating teachers that describes the creation and research behind the REG, it includes how to use the guide with student teachers as well. [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.]