Regarding the blind spots in basic knowledge about currency that brothers have asked about, I recommend a book 'Monetary Economics', and I have also summarized the key points for everyone.

01. Money and Monetary System
Nature and Functions of Money
Nature: General equivalent, medium of commodity exchange.
Functions: Measure of value, means of circulation, means of payment, means of storage, world currency.

Evolution of Currency
Full-value currency → Representative currency → Credit currency → Electronic currency.
Evolution of Payment Systems: Commodity money → Non-redeemable currency → Checks → Electronic payments.

Hierarchy of Currency (China)
M0: Cash in circulation
M1: M0 + Demand deposits from enterprises
M2: M1 + Time deposits from enterprises + Resident savings deposits
M3: M2 + Highly liquid securities (such as financial bonds, commercial papers)

Monetary System
Contents: Currency materials, currency units, primary and secondary currencies, issuance methods (primary currency freely minted/secondary currency state-minted), legal tender capacity (unlimited/limited legal tender).
Evolution: Silver standard → Bimetallic standard → Gold standard (gold coins/gold bars/gold exchange) → Credit currency system.

02. Currency Supply and Demand Equilibrium

Monetary Supply Regulation
Central bank regulates base currency (open market operations, rediscounting, etc.) and monetary multiplier (reserve requirement ratio).
Commercial banks influence monetary supply through excess reserves and borrowing scale.

Monetary Demand Theory
Fisher Equation (MV=PT): Emphasizes the function of medium of exchange.
Cambridge Equation (Md=kPY): Analyzes from the asset perspective.
Keynesian Theory: Transaction motive, precautionary motive, speculative motive.
Friedman Theory: Monetary demand is influenced by permanent income and opportunity cost variables.

Monetary Equilibrium and Disequilibrium
Equilibrium Indicators: Price stability, balance of goods supply and demand, interest rate equilibrium.
Inflation:
Causes: Demand pull, cost push, structural factors.
Countermeasures: Contractionary policies, income indexing.
Deflation: Governed by expansionary policies.

03. Credit and Interest Rates

Forms of Credit
Commercial credit, bank credit, state credit, consumer credit, international credit.

Interest Rate Determination Theory
Classical Theory: Interest rates are determined by savings and investment.
Keynesian Theory: Interest rates are determined by money supply and demand (liquidity preference).
Loanable Funds Theory: Integrates savings, investment, and money supply and demand.

Interest Rate Risk and Term Structure
Risk Structure: Default risk, liquidity, tax impact on interest rate differences.
Term Structure Theory: Expectation theory, market segmentation theory, liquidity premium theory.

04. Financial System and Market

Classification of Financial Markets
Money Market (Short-term): Interbank lending, bill discounting, treasury bills.
Capital Market (Long-term): Stocks, bonds, medium- and long-term loans.
Derivatives Market: Futures, options, swaps (used for risk management).

Financial Institutions
Banking Type: Central bank, commercial banks, policy banks.
Non-banking Type: Securities, insurance, trust, funds.
Financial Functions
Resource allocation, risk transfer, payment clearing, information provision.

Commercial Banks and Central Banks

Functions of Commercial Banks
Credit intermediation, payment intermediation, credit creation, financial services.
Business: Liability business (deposits), asset business (loans), intermediary business (risk-free), off-balance-sheet business (contingent risks).

Functions of Central Banks
Issuing bank, bank of banks (lender of last resort), national bank (agent of the treasury).
Monetary Policy Tools: Reserve requirements, rediscounting, open market operations.

05. International Finance

Exchange Rates and Systems
Quotation Methods: Direct (1 USD = 6 CNY), indirect (1 CNY = 0.16 USD).
Exchange Rate Determination Theory: Purchasing power parity, interest rate parity, balance of payments theory.

Balance of Payments
Accounts: Current account (trade), capital and financial account (investment), reserve assets.
Adjustment of Imbalance: Exchange rate adjustment, monetary policy, fiscal policy.

International Reserves
Foreign exchange reserves (main), gold, SDR (Special Drawing Rights).

06. Financial Regulation and Policy

Basel Accord
Core: Capital adequacy ratio ≥ 8% (core capital ≥ 4%).
Three Pillars: Minimum capital requirements, supervisory review, market discipline.

Monetary Policy Objectives
Price stability, full employment, economic growth, balance of payments.
Transmission Mechanisms: Interest rate channel (Keynes), money supply channel (Friedman).

Financial Innovation and Risk
Motivations: Avoiding regulation, technological progress, risk management.
Types of Risk: Credit risk, market risk, operational risk.

Summary of Core Logic: Money is the blood of economic activity, achieving resource allocation through the financial system (markets + institutions), central banks regulate the economy through monetary policy, international finance involves exchange rates and capital flows, regulation ensures system stability; it's essential for those investing in cryptocurrency/US stocks to understand these logics.