Educators in intentionally small schools in Chicago are working to create a climate that is inviting, engaging, and challenging to some of the most academically disadvantaged students. Over a period of 18 months, data were collected from eight intentionally small schools that included elementary, middle, and high schools; freestanding schools; schools within schools; schools on probation; and schools that predominately enrolled poor and working-class African American and Latino students. Findings from 76 interviews with administrators and staff, 36 focus groups with staff and students, and 137 observations in schools highlighted the importance of professional community, collegial trust, and collaborative work in creating a schoolwide climate for effective education. Factors that contributed to this were philosophical coherence among faculty, a sense of collective responsibility for student welfare, public accountability, shared leadership, teacher collaboration, and a balance between academic concerns and student care. Participation in strong professional communities enabled these practitioners to create engaging and challenging learning experiences for students, who under other circumstances, might have been ignored, poorly educated, or left behind. Instead of relying on the student deficit model to excuse poor teaching and learning, they looked to themselves and their colleagues to improve the process. Some concerns that were identified included teacher burnout, staff fragility, and unfamiliarity with consensus decision making. Teachers in schools within schools often found it difficult to divide their time between their small school and host school. Data from a systemwide study of small high schools suggest some ways that strong professional communities promote student achievement and other positive student outcomes. (Contains 22 references) (TD)