Center for Creative Leadership - Provides helpful links to resources around self-improvement and leadership capacity building.
Bolman, L.G. & Deal, T.E. (2008). Reframing Organizations: Artistry, Choice, and Leadership (4thed). San Francisco: Jossey-Bass.
Heifetz, R., Grashow, A., & Linsky, M. (2009). The Practice of Adaptive Leadership: Tools and Tactics for Changing your Organization and the World. Boston: Harvard Business Press.
Kegan, R., & Lahey, L. (2009). Immunity to Change: How to Overcome It and Unlock the Potential in Yourself and Your Organization. Boston: Harvard Business Review Press.
Leadership Excellence And Dynamic Solutions - Curriculum Notebook - An excellent resource from KSRE for establishing a leadership development program, or for use as a facilitator manual for leadership development.
Getting to YES; Negotiating Agreement Without Giving In. - This book is a pillar in the literature around negotiation.