It is universally acknowledged that teachers are critical to the enhancement of student achievement in schools. This book highlights the significance of teacher leaders as key knowledge workers demonstrating understandings of how new knowledge is created and utilised in relation to schools as productive professional learning communities when teachers engage in learning processes for individual and collective professional development. The case studies of this book focus on the dynamics of how teachers who are engaged in a process of successful school improvement create new knowledge and make significant new meaning. Of particular significance as a result of the research is the postulation of a new image of the professional teacher - one who recognises his/her capacity for engagement in collective, reflective practices through the exercise of new ways of thinking and acting in support of student achievement. This study reveals that collective intelligence in schools is more than just the sum of individual processes or capabilities, it is the capacity of collaborative individuals to collectively grasp, synergise and create meaning together.