This document provides an overview of monetary and banking systems. It defines money and discusses its origins, characteristics, types, and functions. It examines the demand for money, including transactions, precautionary, and speculative demand. It also discusses the money supply in Sri Lanka and classifies it into different monetary aggregates like M1 (narrow money supply), M2 (broad money supply), and M2b (consolidated broad money). Finally, it discusses the role of the central bank in providing monetary aggregates and regulating the financial system.