This is a theory applicable to agrarian societies and it seems to be pretty well fit into real historical data. The core idea is somewhat Malthusian, connecting growth population to development cycles of society. In short most of conditions depend on ratio of available natural resources to population. The cycle goes through several stages:
1. Expansion – population is small and there is enough arable land to feed it well. It results in population and society growth until it hit some natural o human barrier – borders of powerful neighbor, or geographical limits like oceans.
2. Stagnation starts when the limit achieved and there is no place to expand. Long period of stability with slowly declined quality of life follows for a while.
3. This stagnation period ends by decline usually not expected and quite dramatic often connected to epidemics of contagious disease, or invasion, or some other cataclysm that dramatically decrease population and changes structure of society to some new form in which the cycle starts from the beginning.

The book reviews in details 8 such cycles:
2 for England – Plantagenet cycle (1150-1485) and Tudor-Stuart (1485- 1730)
2 for France – Capetian Cycle (1150-1450) and Valois (1450-1660)
2 for Rome – Republican Cycle (350-30 BCE) and Principate (30 BCE – 285 CE)
2 for Russian – Muscovy Cycle (1460-1620) and Romanovs (1620-1922)

All cycles last between 200 and 350 years and include stages of Expansion, Stagflation, Crisis and Disintegration.

Very interesting is discussion for each cycle of elite’s structure and behavior. It looks like one of necessary condition of disintegration in addition to unsustainable level of population is break down of elite into warring parties of approximately equal strength so nobody can achieve decisive victory until society disintegration is completed and it is ready for the new cycle.

I guess it looks like we are now at similar point, though our society is not agrarian and our elite seems to be not that keen on killing each other, it is rather fight on paper and in the voting booth. However I think outcome of the fight will be a new cycle of reformed society, only this time without population decrease.