Religious people can easily classify societies into good and bad because they have a clear value framework but sociologists as objective viewers of society cannot do so easily. One thing is clear: to look for perfectibility of society is to look for change. This lecture explains how societies change. Although all societies are continuously changing, sometime at a very slow pace and sometimes fast, but sociologists define social change in a particular manner, meaning thereby that all types of changes do not imply social change. The term social change covers only those changes which involve change in the social structure, i.e., in “the sum total of normative behavior – the sum total of social relationships which are governed by norms” (Haralambos et al., 2000, 10). Thus to say that society is changing is to say that the structure of institutions – economic, political, religious, recreational and marriage etc. – is changing. Here the term institution refers to “a set of interwoven folkways, mores, and laws built around one or more functions (Davis, 71). Changes in mere size and density of population, beliefs, religious practices etc. may be important but would not in themselves constitute social change. They may, of course, facilitate social change. For example, change is size of population may lead to specialization and division of labor which exhibits social change.