The Academy for Educational Development (AED) conducted a case study of six public high schools in New York City as part of a multifaceted evaluation of a small schools initiative funded by the Bill & Melinda Gates Foundation. Through surveys, interviews, and focus groups, the authors gathered information and opinions from the schools' principals, teachers, support staff, and students. They also conducted observations of classes and meetings to gather data about practices related to such vital matters as personalization, classroom instruction, college preparation, and staff collaboration. The Bill & Melinda Gates Foundation initiative tapped the expertise of intermediary organizations that provided direct supports to schools. An important part of this case study, then, was to explore how the intermediaries supported schools and how school personnel perceived the intermediaries' interventions. Guided by the research literature on effective school and classroom practices, the case study looked for evidence of the following practices related to high-quality education: (1) Intermediary support; (2) Personal and academic support; (3) Effective instructional practices; and (4) College preparation. All of the case-study schools conveyed a college-going culture to students and parents through multiple methods, and students indicated that they got the message. All of the case-study schools offered students college access activities (such as preparing for and taking entrance exams and completing college and financial aid applications) and attended to college readiness skills (the skills and abilities required to do college-level work) in their classrooms to some extent. Nonetheless, the case-study data suggest that schools approached college preparation differently. Specifically, some schools used an integrated approach while others used a compartmentalized approach. The findings of this case study suggests that some schools were more successful than others in providing personal and academic support for students, delivering effective instruction, and promoting college preparedness. The support of the intermediary organizations seemed to be a key factor in the relative success of these schools. Appendices include: (1) All Instruments Used in Case Study of Gates Small High Schools; and (2) Response Rates & Respondent Characteristics. Individual sections contain footnotes. (Contains 6 figures and 24 tables.)