The use of student thinking in teaching has been linked to improved instruction and learning. It is reasonable to assume that the University of Delaware's undergraduate program might be interested in figuring out ways to develop this skill in its mathematics specialist pre-service teachers. Currently, the student teaching experience at the University of Delaware (UD) requires student teachers to complete an integrated unit plan during "both" 9-week sessions. The problem is that the unit assignment does not focus pre-service teachers' attention on student thinking. Lesson study has been proposed as a process that helps "practicing" teachers develop this skill and disposition. The goal of this study is to investigate how, if at all, "pre-service" teachers at the University of Delaware engaging in the lesson study process during their student teaching experience develop the abilities to plan and revise their teaching with their students' thinking in mind. Based on the results, a recommendation for using lesson study (or an activity similar to it) in the University of Delaware's undergraduate program will be made. [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.]