Because leadership theories and recent research into principals' roles have only limited validity, practical utility, and comprehensiveness, this study undertakes a description of effective principals' behaviors and a coherent explanation of them. Long-term goals, factors affecting student learning, strategies for goal achievement, and structures of decision-making were identified as the central arenas of principal effectiveness. Starting with the profiles of the ideal principal developed by two groups of school-based practitioners, researchers modified the resulting profiles through interviews with 90 principals, producing a four-stage growth profile of effectiveness. Within each of the four arenas of principal effectiveness (goals, factors, strategies, and decision making), researchers found four descending orders of roles, the highest being systematic problem-solving, followed by program management, humanitarianism, and administration. (JW)