This is the third in a Series of five manuals produced by the Social Security Department of the ILO to provide the reader with information on all the major elements of social security, including the principles, administration, financing, pension schemes and social health insurance. The topic here is financing and the manual looks at social protection systems and their economic environment. It examines in detail the principles of financing and financial systems, including the flow of funds in a social security system, short- and long-term benefits and their respective financial systems and administration, as well as the actuarial and statistical methods and investment policies and instruments