In-depth studies in the field of K-12 education confirm that investments in high-quality, research-based leadership development for school systems can directly impact student success--in the classroom and beyond. This results in the need to learn beyond content mastery and develop deeper learning skills. Students need to be able to adapt quickly, be continuous learners, and able to collaborate across many social boundaries. Success in the 21st Century depends on critical thinking, communication, and collaboration. Building students' capacity for this new era requires investments in teacher and administrator professional development to create the educational ecosystems that foster students' mastery of these skills. A growing body of work by the Center for Creative Leadership (CCL®), a global nonprofit with a 50-year track record of innovation in developing leaders, shows that investments in leadership development for principals, teachers, staff, and students play an essential role in creating the transformational change needed in education today. That's because leadership development focuses on the single most important part of any school system, public or private--its people. And now more than ever, meeting the complex challenges of a rapidly changing world requires schools to equip young people with the skills they need to become productive workers, engaged citizens, entrepreneurs, and lifelong learners.