The key argument of the book is that the economy is not inherently self-correcting, and that government intervention is necessary to stabilise the economy and ensure full employment.

In particular, Keynes argued that in times of economic downturns, government spending should be increased to boost aggregate demand and stimulate economic activity. He also proposed that the central bank should be able to actively adjust interest rates to stabilise the economy although monetary policy might become ineffective if an economy is in a liquidity trap.

Another important aspect of the General Theory is the distinction of the "classical" and "Keynesian" macroeconomic theory. He challenged the neoclassical belief that the economy tends towards full employment and that government policies to stabilize the economy would be ineffective, or even harmful.

Additionally, the book also introduces the concept of "animal spirits", which refers to the psychological and emotional factors that influence economic decision-making, such as confidence and fear.

In summary, Keynes's "General Theory of Employment, Interest and Money" provides a theoretical framework for understanding the role of government and monetary policy in stabilising the economy and promoting full employment.

It challenged the prevailing economic thinking of the time and had a profound impact on economic policy and thought in the decades that followed its publication.

Monetarism is a theory that challenged many Keynesian ideas. It became popular in the 1970s and 1980s - decades characterised by high and volatile inflation.