The author built upon the brilliant work of the Russian Tchijevsky who discovered that human activity, from powerful social movements to wars, are all governed by the 11-year solar cycle, i.e. the solar minimum and maximum, with lots of sun spots at the solar maximum. If you doubt the verity of this, then research the effect of the sun on terrestrial earthquake activity, recently published in the science journals.

The authors discovered 4 sub-cycles of the 11-year solar cycle, and describe their effect on human activity.