This article deals with the processes of authority and power. Power is defined as an influence over others, i.e., one's ability to cause change in the cognition, attitude, behaviour and/or emotion of others. Depending upon its various sources, eight different types of power have been distinguished. These are: informational power, expert power, coercive power, reward power, referent power, authoritative power, indebted power, and deferent power. It has been suggested that, to be effective and durable, all social powers, regardless of their sources, should be legitimate. It has also been recognized that power seldom comes from one separate source and its effective use depends upon several factors. It has been admitted that, of all the sources of power, information appears to be the most stable and the most befitting of a value that respects individual freedom of choice.