Monetary theory is less abstract than some economic theory in the sense that it cannot avoid a relation to reality. Its development has been to a considerable extent prompted by the experiences encountered by the writers in their own time, and monetary disturbances have always acted as a catalyst in its development. It seems that the role of money in an econmy has appeared to be more important in some periods than others, and writers on monetaryu issues, have therefore, had to adjust their theories accordingly.