In my previous column, I argued that 1) a professional is obligated to seek and apply best practice when serving clients; 2) it is evident that the best practice for meeting the needs of students and improving professional practice in schools is to build a collaborative culture; and 3) educational leaders should, therefore, focus their improvement efforts on building a collaborative culture in their districts and schools. Calls for a collaborative culture come from leading educational researchers who use unusually emphatic language. Milbrey McLaughlin and Joan Talbert (2001) found that effective high schools and effective departments within high schools were characterized by powerful professional collaboration. Kenneth Eastwood and Karen Seashore Louis (1992) concluded that creating a collaborative environment featuring cooperative problem solving was the single most important factor in successful school restructuring. Fred Newmann and Gary Wehlage (1995) found that nurturing a