This study examines the leadership and management skills needed to improve urban high schools. Information was drawn from a national survey of 178 urban high school principals whose schools had been conducting serious improvement efforts for up to 4 years and in-depth case studies of five large high schools in the following urban areas: (1) Boston; (2) New York; (3) New Jersey; (4) Cleveland; and (5) Los Angeles. The following summary findings are discussed in terms of their implications for districts and schools and the issues of will and skill involved in implementation: (1) schools and their districts must be actively engaged with each other, but with few rules and much autonomy for the school to choose goals and strategies; (2) planning should be evolutionary and works best through a cross-role group of people who may not normally work together; (3) a shared vision of what the school is to become is an important feature guiding improvement; (4) from $50,000 to $100,000 annually for several years is needed for serious change efforts; and (5) problems must be confronted actively, promptly, and in depth. Discussions of the research methodology, nine tables of statistical data, and a list of 155 references are appended. (FMW)