Over the past decade, alternative teacher preparation programs have proliferated across the nation -- and in Massachusetts -- in response to projected teacher shortages and in an effort to better prepare teachers for the challenges of today's classrooms. While the vast majority of Massachusetts teachers are trained through traditional teacher preparation programs, both the number of alternative route programs and the number of teachers completing them has grown significantly. National research comparing alternative and traditional routes to teaching offers little empirical evidence to guide policy changes. Yet there has been a shift in teacher preparation programs toward: longer and more intense field-based experiences; closing the gap between theory and practice; partnerships between preparation programs and local school districts; and accountability in teacher preparation. It is within this context that the Rennie Center embarked upon a project to examine the role of alternative routes to teaching in Massachusetts. As part of this project, the Rennie Center convened a diverse working group, which examined the characteristics of alternative teacher preparation programs in the Commonwealth, including the type of candidates they attract, and examined issues associated with the expansion and sustainability of these programs. This report is the culmination of the Rennie Center's year-long project. Preparing Tomorrow's Teachers: The Role of Practice-Based Teacher Preparation Programs in Massachusetts highlights gaps in knowledge and areas for improvement, and lays the groundwork necessary for a deeper look at issues associated with drawing exceptional candidates into the teaching profession; filling vacant positions; measuring teacher quality; and holding teacher preparation programs accountable. The final section of the report puts forth considerations for policymakers, K-12 school and district leaders, and institutions of higher education. The report encourages the state to facilitate and encourage communication and collaboration between those that train teachers and those that hire them, and provide teacher preparation programs with access to the state data system so they may more easily evaluate their programs. The report also encourages K-12 district leaders and deans of college and university departments of education to create lend-lease programs that would allow expert teachers to work as adjunct professors in schools of education without forfeiting their role as K-12 teachers as a way to bring both the clinical and contextualized knowledge of schools and districts into teacher training. The report was the subject of discussion at a public event on November 19, 2009.