This article by Darling-Hammond and McLaughlin examines the conditions under which teachers acquire and use new knowledge and skills, focusing on effective models of professional development. They explore the role of teachers as learners and practitioners, new designs for professional development, school culture, critical inquiry, elements of effective curriculum frameworks, and lessons learned for educational policymakers. The authors argue that the success of educational reform depends on teachers' ability to reflect on their practice, build new roles in the classroom, and adopt new teaching methods. They emphasize the need for policies that support teachers in learning and reflecting critically about their practice, rather than simply acquiring new skills or knowledge. The article also discusses the importance of institutional structures and partnerships that foster collaborative learning and professional growth, such as Professional Development Schools (PDS) and networks of teachers and schools. Additionally, it highlights the need for strategic evaluation of existing policies to ensure they align with the goals of teacher development and systemic reform. The authors conclude by outlining policy recommendations to support professional development, including the allocation of resources for specific local needs, the promotion of collaborative learning, and the restructuring of school leadership roles to foster a culture of learning and reflection.This article by Darling-Hammond and McLaughlin examines the conditions under which teachers acquire and use new knowledge and skills, focusing on effective models of professional development. They explore the role of teachers as learners and practitioners, new designs for professional development, school culture, critical inquiry, elements of effective curriculum frameworks, and lessons learned for educational policymakers. The authors argue that the success of educational reform depends on teachers' ability to reflect on their practice, build new roles in the classroom, and adopt new teaching methods. They emphasize the need for policies that support teachers in learning and reflecting critically about their practice, rather than simply acquiring new skills or knowledge. The article also discusses the importance of institutional structures and partnerships that foster collaborative learning and professional growth, such as Professional Development Schools (PDS) and networks of teachers and schools. Additionally, it highlights the need for strategic evaluation of existing policies to ensure they align with the goals of teacher development and systemic reform. The authors conclude by outlining policy recommendations to support professional development, including the allocation of resources for specific local needs, the promotion of collaborative learning, and the restructuring of school leadership roles to foster a culture of learning and reflection.