With the financial liberalization and the development of financial technology in recent decades, in order to obtain new sources of income, the business scope of financial institutions has expanded from traditional interest-bearing business to non-traditional business such as handling fees, commissions, insurance underwriting and investment banking services. This process is usually accompanied by the diversification of bank products and services. Therefore, this book takes the diversified operation of banks as the research object and defines diversified operation as the range of business activities that banks can engage in and the process by which banks can generate income from different other businesses or services.