There are multiple explanations for why many children do not have access to well-prepared pre-K teachers. The five programs profiled in this report show that it is possible to give pre-K teachers rich, research-based training that prepares them to work with young children. However, there is a scarcity of opportunities focused on the developmental needs of young children and most programs lack the funding to execute them well. The five profiles show how communities within New Jersey, Texas, Illinois, Tennessee, and California are strengthening pre-K teachers' knowledge and competencies to ensure that they are effectively prepared to work with young children. This report includes a range of models at different stages in their development that are taking different approaches to professional learning and focusing on different content areas. Researchers sought out local models that were being evaluated for their effectiveness, because as Curry School of Education explains, while there are agreed-upon components of high quality professional learning, there is also evidence that many well-designed professional learning programs do not improve teacher practice or child outcomes. These five programs, while different from one another, each incorporate multiple aspects of what experts have determined to be high-quality professional learning. These program profiles illustrate that offering high-quality professional learning requires planning and careful implementation. Programs need to create structures and content that align with the research about how both adults and children learn best. Five lessons for professional learning design and implementation emerged from research on these programs: (1) Embrace that high-quality professional learning is an investment of time and money; (2) Help teachers and administrators see the value early on; (3) Develop opportunities for teacher leadership and growth; (4) Coach the coaches; and (5) Align the program model with the latest research on professional learning and use evaluation tools for continuous improvement.