Teachers are continually confronted with meeting the needs of all students and preparing them to be successful on state end-of-course assessments while changing or evolving to be more of a facilitator of student-centered. Lessons are to be relevant for the students, engaging them so they are active participants in their learning. However, many teachers have never experienced rich tasks or observed a classroom where this approach is customary. The purpose of this study is to discover if activities during a professional development on rich task creation will influence the Algebra I teacher team's planning of instruction and facilitating lessons. A descriptive case study approach is used to focus on the teachers and their growth during the Summer Institute and the school year lesson study. The question that drives the research is: How does the Summer Institute on rich tasks influence the teacher's implementation of the lesson study process? Secondary research questions delve into the participants' growth and actions during the professional development and the lesson study: 1. What did teachers perceive as characteristics of "high cognitive demand" tasks prior to and after professional development? 2. What were the goal(s) of the teacher and teacher team prior to, during, and after the professional development? 3. How did the group-focused experiences of rich tasks influence teacher practices and beliefs during lesson study? 4. What challenges and/or constraints did teachers encounter when implementing rich tasks in the lesson study? The focus is on the teacher's willingness to use a lesson study approach that combines quantitative data (content assessment and planning quality) with qualitative data (interviews, field notes, journaling, lesson study briefing and debriefing, and observations). There are two phases to the study. The first phase is a Summer Institute in which teachers will learn about and develop rich tasks; the second phase is the implementation of the task through a lesson study approach in which teachers will self-evaluate. The results of the study showed that teacher change is more complex than just having teachers experience and develop rich tasks. Developing the course flow that correlates with the big ideas needs to be understood by the teachers and have teacher buy-in, support and time need to be a top priority with all leaders in agreement, and teachers need to plan the units and lessons in writing so thoughts may be thoroughly explored and explained. [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.]