Educators are people involved in the practice of education. Education theory can refer to either a normative or a descriptive theory of education. In the first case, a theory means a postulation about what ought to be. It provides the “goals, norms, and standards for conducting the process of education.” In the second case, it means “an hypothesis or set of hypotheses that have been verified by observation and experiment.” A descriptive theory of education can be thought of as a conceptual scheme that ties together various “otherwise discrete particulars. For example, a cultural theory of education shows how the concept of culture can be used to organize and unify the variety of facts about how and what people learn.” Likewise, for example, there is the behaviourist theory of education that comes from educational psychology and the functionalist theory of education that comes from sociology of education. It has been argued that high rates of education are essential for countries to be able to achieve high levels of economic growth. Empirical analyses tend to support the theoretical prediction that poor countries should grow faster than rich countries because they can adopt cutting edge technologies already tried and tested by rich countries. This biographical encyclopaedia provides readers with of some of the basic knowledge of World Great Educators.