How do leaders best make a difference? In business and in society, we are moving away from the archetype of a dominant, authoritative leader as well as the formal hierarchies that supported and produced that traditional form of leadership. Globalization, disruptive technologies, and a renewed focus on teams have flattened hierarchies and distributed authority throughout the enterprise. Exploring this fundamental question has brought together the leadership development agendas of The Wharton School and the McNulty Foundation, and will guide our next phase of innovation and expansion.