At 4 o’clock on a Monday afternoon, more than an hour after students have left, 30 teachers gather in a classroom at the district office to discuss leadership styles in a seminar co-taught by a Northern Illinois University professor and a district administrator. Across the hall, another cohort studies instructional strategies, looking for strengths and weaknesses. For three hours, both groups discuss and reflect, preparing to bring new expertise back to their departments and students, and they will continue to do so over the next 14 weeks. This is effective ongoing professional development, and it has been taking place for 10 years. Community High School District 155 in Crystal Lake, Ill., and Northern Illinois University (NIU) College of Education engaged in a partnership that has