The General Theory of Employment, Interest and Money (Chinese Edition) by John Maynard Keynes

The General Theory of Employment, Interest and Money holds that apart from the Frictional unemployment and voluntary unemployment defined by the traditional economics, there is another kind named involuntary unemployment, caused by the deficiency of the aggregate demand or effective demand, in turn caused by of Investment demand and consumer demand. The deficiency of the former results from consumer tendency, the expectant profits of capitals and the liquidity preference of money, while of the latter from the lagging behind of the income increase to the consumption increase. The deficiency of the investment demand is caused by Capital efficiency decrease and liquidity preference, with the former referring to while the latter the preference of holding cash back.