An $11 million executive-training course for principals, modeled after best practices used in the corporate, medical, engineering, and military worlds, is starting to gain traction among states. Developed by the National Institute for School Leadership, or NISL, a for-profit company based in Washington, the program is now used widely in Massachusetts, Minnesota, Mississippi, and Pennsylvania, as well as in individual school districts in five other states. Computerized simulations designed to help prepare principals who are instructional leaders lie at the heart of the 14-unit curriculum. The curriculum includes such topics as the principal as strategic thinker, leadership for excellence in literacy and mathematics, the principal as team builder, and the principal as ethical leader. It is designed to develop school leaders with a sharp focus on improving instruction and raising student achievement through a combination of case studies from business, education, and the military; face-to-face instruction; professional readings; video commentaries by leading experts; computer-assisted instruction; and "action research" projects. [This article was produced by Editorial Projects in Education, Bethesda, MD.]