A must-have read - on economics

What odds would you get, I wonder, if you'd bet two months ago that the bestselling book on Amazon.com would be a 700-page, data-heavy tome by a previously obscure French economist?

That, for the best part of a month, Capital in the 21st Century would be outselling all the teenage vampire books, all the self-help brochures and all the thrillers ever written?

For the past 15 years or so, Thomas Piketty, a Paris economist, has led a revolution in the study of inequality. Prior to his research, the discipline had been unable to describe how well the very richest people in society - the top 1%, and even the top 0.5% and 0.1% - were doing compared with the rest of us.

Having developed the techniques to do this, Piketty showed that by far the most important dynamic in the evolution of inequality in the late 20th and early 21st centuries was the astonishing rate at which the truly rich were pulling away from everyone else.

He estimates, for example, that 60% of the increase in GDP in the US between 1977 and 2007 accrued to just 1% of the population. Overall, that means that for every $1 increase in income of the bottom 99%, people in the top 1% got $15.

Piketty's book is a description of how levels of inequality have changed in Europe, the US and a few other countries for which the data exist.

He shows that inequality was highest at the start of the 20th century, and argues that the decline in inequality in most of the world during the second half of the last century is the result of historically unique circumstances that are not likely to occur again.

In contrast to this benign social transformation, the 21st century will mark the rise (again) of "patrimonial capitalism" - a society in which a smaller and smaller elite owns a larger and larger share of economic assets, and in which inheritance, instead of merit or education, plays the decisive role in determining who is in this elite and who is not.

To summarise Piketty's argument, the decline in inequality during the 20th century was due to a series of inflationary episodes and global wars that destroyed the assets of many of the richest dynasties.

This, together with unprecedented economic growth, as well as the imposition of much higher taxes on the rich, created the circumstances for the emergence, for the first time in history, of a relatively large, property-owning middle class.

Piketty thinks this is unlikely to be the dominant pattern in the 21st century. He thinks economic growth will slow and, as it does, a large gap will open between the returns on owning assets and the average rate of growth.

The wider the gap, the faster assets will accumulate in a narrower and narrower band of people.

The only thing that can stop this, he thinks, are taxes on wealth, taxes that would have to be global in reach if they were to work. Little wonder that some critics have done little more than call him a communist, wipe their hands and tell people to move along.

Capital in the 21st Century is a dense book but Piketty explains himself slowly enough to make sure that readers understand the import of what he is saying.

Maybe that, as much as anything, explains the phenomenal sales, which are expected to reach 200000 in hardcover in the next few months.

If Piketty is right, the next few generations could see as stunning a transformation of society as did our parents and grandparents.

And, by the time it's over, the world will end up looking less like the dream of meritocracy in Harry Potter's Hogwarts and more like something out of The Hunger Games.

• Altbeker is a writer and researcher