The SDR was created in 1969, during the Bretton Woods fixed exchange-rate system, because of concerns that there was insufficient liquidity to support global economic activity.

The economic collapse, when inflows of capital halt, can be very painful - even more so if a fixed exchange rate (or currency union) demands a period of falling nominal wages and prices.

The thing that the authors put most emphasis on is the role of surplus countries in fixed exchange-rate schemes.