Educational psychology is the study of how humans learn in educational settings, the effectiveness of educational interventions, the psychology of teaching and the social psychology of schools as organizations. Although the terms educational psychology and, school psychology are often used interchangeably, researchers and theorists are likely to be identified as educational psychologists, whereas practitioners in schools or school-related settings are identified as school psychologists. The research methods used in educational psychology tend to be drawn from psychology and other social sciences. There is also a history of significant methodological innovation by educational psychologists, and psychologists investigating educational problems, Research methods address problems in both research design and data analysis. The Present work is a treatise on the rives and contributions of World Great Educational Psychologists. lt should be of immense interest and inspiration for all the students, academics and general readers alike.