Тhe article discusses existing theories of money, their advantages and disadvantages. The commonalities and differences in existing theories of money are revealed. The author's classification of theories of money is given. The concept of negentropy is substantiated as the methodological basis of the negentropic approach to substantiating the essence of money. The objective negentropic nature of money as a commodity is revealed. The subjective nature of money based on trust is shown. The essence of money as a universal equivalent of the stock of negentropy is revealed. An explanation of the functions of money is given from the point of view of the negentropy approach. Inflation is considered as a manifestation of the entropy of money itself. The laws of monetary circulation are explained from the point of view of the negentropy approach. Existing theories of money are considered as special cases of negentropy theory. Recommendations are given for regulating money circulation, taking into account the negentropic nature of money.