In today's school communities the critical friend or change facilitator has an increasingly vital role to play across the spectrum of teaching and learning, health promotion and continuing professional development. But what is a critical friend and what does it take to be effective in the role? Drawing on the findings of three intensive, school-based research initiatives, The Critical Friend: Facilitating positive change in school communities clearly defines the role and demonstrates a range of frameworks and applications for practice. Positive change in students' social and emotional wellbeing and connectedness to school is promoted through teachers' professional learning and a focus on supportive school environments.