This study conducted a bibliometric analysis for the purpose of identifying the crucial leadership constructs that best explain and/or define effective educational leadership in two decades (1990-2000 and 2001-2010). The study reviewed top authors in educational leadership and analyzed their top cited works to identify leadership constructs which were (a) unique to leadership works within the 1990-2000 decade, (b) unique to the 2001-2010 decade, and c) similar or different between the two decades. The study found that the leadership constructs did evolve and shift during the study period and addressed the changing demands of individuals, educational organizations, and the external environment. Crucial educational leadership constructs were the product of the efforts of researchers in educational leadership to promote effective school leadership, improve learning outcomes and student performance, and create beneficial organizational results. The findings of the study highlight the potential impact and benefit of the continually upgrading and refreshing the understanding, training, and preparation of current and future school leaders. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]