Bernard Bass and his wife Ruth set forth and provided a comprehensive meta-analysis of leadership regardless of desired application, "The Bass Handbook of Leadership: Theory, Research, and Managerial Applications. Whether an academic or in the private sector, this text is a must-have reference. This text provides you the research behind almost any leadership concept or definition. While more of a textbook in format, the usefulness of such a reference is indispensable. Better than any office manual covering leadership. Worth spending time just thumbing through for personal curiosity.