The 3 major theories of economics are Keynesian economics, Neoclassical economics, and Marxian economics. Some of the other theories of economics are monetarism, institutional economics, constitutional economics etc.You can read about the Monetary System – Types of Monetary System (Commodity, Commodity-Based, Fiat Money) in the given link.
Further readings:
- National Institution for Transforming India (NITI Aayog) – A Brief Overview
- Monetary Policy – Objectives, Roles and Instruments (UPSC Indian Economy)
Comments