When teachers are supported to work together in ways that allow them to deepen knowledge of their professional practice, the understandings that emerge from their conversations about quality learning and teaching demonstrate a high level of expertise. Yet such professional knowledge is often deeply embedded within each teacher's everyday teaching; the tacit knowledge that determines how and why they attend to student learning in certain ways. This book captures the professional knowledge of teachers that developed as the result of an ongoing process of school based change, where teachers began to work differently because they began to think differently about the learning that mattered for their students in their school. The explication of their knowledge of practice became possible due to the ongoing support they received from their school leadership - in most part because leadership trusted them as professionals to responsibly lead student learning. Within this culture of trust and valued collaboration, working alongside external critical friends who supported their professional learning, the teachers engaged in regular, thought provoking and interactive professional dialogue. Together they exposed and challenged each other's thinking and beliefs about learning and teaching, captured and examined each other's practice and, ultimately articulated and extended their professional knowledge. The insights about this collaborative learning process and the emergent knowledge and understandings teachers develop about the interactive relationship between learning and teaching, has much to contribute to educational discourse beyond the school setting. Some of that knowledge and the way it looks in practice is shared in this book.