In his General Theory published in 1936, John Maynard Keynes wrote that the source of all employment in a market economy is spending - business and household (consumer) - - and that the Depression occurred because The collapse of the banking system after 1929 had led to a contraction of the money supply, which caused a decline in purchasing power. O The economic slowdown after 1926 had led to production cuts and lower employment, leading to a decline in both business and consumer spending. O By 1930 low profits and exhaustion of investment opportunities reduced business spending to levels insufficient to create high levels of employment. By 1932 one-quarter of the workforce was unemployed and farm income had dropped from $12 billion to $4 billion. reducing consumer spending